Study Guide Department of Statistics Faculty of Natural and Agricultural Sciences Mathematical Statistics WST 121 Table of Contents Contents 1 Introduction ................................................................................................................. 1 1.1 1.2 1.3 1.3.1 2. Welcome.......................................................................................................................... 1 Educational approach ....................................................................................................... 1 Responsibilities of the student ......................................................................................... 2 Semester planner WST121 ................................................................................................................ 4 Administrative information.......................................................................................... 5 2.1 2.2 2.3 Contact details ................................................................................................................. 5 Timetable ......................................................................................................................... 6 Study material and purchases........................................................................................... 7 3. Assessments .................................................................................................................. 8 3.1 3.2 3.3 Assessment plan .............................................................................................................. 8 Semester mark calculation ............................................................................................... 9 Assessment policy ............................................................................................................ 9 3.3.1 Procedure to be followed when a semester test cannot be written ................................................... 10 3.4 3.5 3.6 3.6.1 3.6.2 4 Plagiarism ...................................................................................................................... 11 Programme/Departmental/Module rules, requirements and guidelines ........................ 12 Code of conduct ............................................................................................................. 13 Communication via email (wst121stats@gmail.com) ...................................................................... 13 Compliments and complaints .......................................................................................................... 13 Module information................................................................................................... 14 4.1 4.2 4.3 4.4 4.5 4.6 4.7 Purpose of the module ................................................................................................... 14 Module outcomes .......................................................................................................... 14 Articulation with other modules in the programme ........................................................ 14 Module structure ........................................................................................................... 15 Learning presumed to be in place ................................................................................... 15 Credit map and notional hours ....................................................................................... 15 Units .............................................................................................................................. 16 Unit: Statistics and Sampling Distributions ...........................................................................................16 Unit: Point estimation .........................................................................................................................17 Unit: Statistical intervals based on a single sample ...............................................................................17 Unit: Tests of hypotheses based on a single sample..............................................................................18 Unit: Inferences based on two samples ................................................................................................19 Unit: Analysis of Variance ....................................................................................................................20 Unit: Regression and correlation .......................................................................................................... 21 Unit: Goodness-of-fit tests and categorical data analysis ......................................................................22 Unit: Alternative approaches to inference ............................................................................................23 5 Support services ............................................................................................................ 24 E-learning support ..................................................................................................................... 24 Other support services .............................................................................................................. 24 Annexure 1 ....................................................................................................................... 25 1 Introduction 1.1 Welcome A hearty welcome to all students who are doing Mathematical Statistics 121 – the last stretch of first year Mathematical Statistics. This is your second step towards the “sexiest career of the 21st century” – whether it is called statistics, data analysis or data science. But heed some wise words: “Don’t let what you cannot do interfere with what you can do.” – John Wooden “There are no shortcuts to any place worth going.” – Beverly Sills “There is no substitute for hard work.” – Thomas Edison You’ll be in the experienced hands of lecturers: Dr Seite Makgai (Course coordinator) Chapters 9, 10, 11, 12 Dr Najmeh Rad Chapters 6, 7, 8 & 13, 14 1.2 Educational approach Lecturers should be seen as facilitators rather than conveyors of knowledge. It is your responsibility to engage, utilize and capitalize on all learning opportunities. Quality instruction requires students to diligently prepare for lectures, tutorials and practicals, as this enables teaching to build actively on common prior knowledge. We will be functioning in a hybrid environment consisting of both online and in-person activities. Details of each week’s activities will be posted weekly on ClickUP. 1 © 2023 University of Pretoria: Adapted for NAS ClickUP Roadmap: • Administrative matters, which includes Announcements, Lecturers & Tutor information, will be posted under Admin. • Throughout the course of the semester, information will be regularly posted under Announcements. These announcements will include test information (scope, arrangements, etc.), various other updates, etc. Please check for announcements regularly (at least twice a day). A weekly schedule detailing what needs to be covered on a weekly basis will be posted under the Weekly Schedule page. Under the Study Material division, you will find: o The study guide is included under this division. Please read this study guide thoroughly. o Information regarding the textbook and the instructions to access it via the library will also be placed under the Study Material division. o Lecture material (Some additional material-if necessary will be posted under this page. Please note that not all Chapters 6-14 will have additional material.) o Assessment Material (memorandums of semester tests, formula sheets and tables) will be also be posted under the Study Material division. • • • • • Under the Tutorials & Practicals division you will find: o Tutorials (Question worksheets, tutorial assignment submission links and memos) o Practicals (Question worksheets, practical assignment submission links and memos) Your marks for tests, tutorial and practical assignments, as well as any other assessments can be found under My Grades. Under the Online lectures & interaction division you will find: o Lecturers and tutors consultation hours (these times will be announced). o Discussion board forums to post any/all of your content related questions. o Class collaborate for any live online lectures. The recordings, if available, can also be found under the Class Collaborate page. Content will be added to these sections during the course of the semester. 2 © 2023 University of Pretoria: Adapted for NAS 1.3 Responsibilities of the student ⇒ Start your studies with the determination to make a success of it. Tertiary studies require a lot of sacrifice, perseverance and hard work and all this still does not mean you cannot fail. But remember where there is a will there is a way. ⇒ The tempo of the semester is extremely fast, so falling behind could be detrimental to your performance. Construct a study schedule, and keep to it! See to it that you revise all your subjects at least once a week and that you understand all the work. If you fall behind, try to catch up within one week. Guard against the mistake of concentrating on one subject during test periods. ⇒ Work through all the lectures as indicated by the weekly plan posted. Discipline yourself to keep to the schedule as posted every week. Concentrate on the explanations and use the terminology and notation of the subject. You need to learn the statistical language in order to communicate the concepts! ⇒ Take immediate steps if you see that you are not making progress with your studies or if you are losing interest. If a problem arises, deal with it as soon as possible. Talk to someone who can help you, and remember no one can help you if they do not know about your problem. The lecturers and tutors and student advisors are available online to see to your needs. ⇒ The subject Mathematical Statistics, as the name indicates, is more mathematical in nature. All the new terminology is based on the old, which has to be known. Do your best to understand the work that is done each day. Post on the discussion board if something is not clear to you. ⇒ Mathematical Statistics is a study subject that cannot be mastered within a day or two. During the preparations for any test, it is important that you write out the definitions, concepts, propositions and proofs related to the scope of the test. In this way, you improve your concentration and thus will know your work sooner. ⇒ See to it that you understand the subject in its entirety. Schematic representations and tables of summations can help you to achieve this. This takes a lot of time but is always worth the effort when it comes to revising the work. ⇒ Always be proud of your work. Keep it systematic and neat. If something does not make any sense, do it over and do it correctly. Do not settle for anything less than the best. ⇒ Don't be an academic wreck! Vary you study time by doing sport or any other recreational activity. But do not over indulge in the last two. Remember you enrolled at university to study and get your degree. To end with: successful studies depend on you being MOTIVATED. If a course in this department is included in your curriculum, you can accept that there is a good reason why this is so. On the next page find a calendar which gives an indication of weekly activities. On ClickUP an updated list of activities is published weekly and stored afterwards in case you missed something or need a reminder of what was done during a particular week. 3 © 2023 University of Pretoria: Adapted for NAS Semester planner WST121 Week (lectures per week) Date* General** Content 1 (4) 24-28 July 6.1-6.2 2 (4) 31 Jul-4 Aug 6.3-6.4 3 (3) 4 (4) 7-11 Aug (9=PH) 14-18 Aug 5 (4) 21-25 Aug 6 (4) Tutorial Practical Tutorial Test (During the Tutorial Session) Lecturer in charge*** 0 N 1 1 N 7.1 1 1 8.1-8.2 2 2 N 8.3-8.4 3 3 N 28 Aug-1 Sep 9.1-9.2 3 3 S 7 (4) 4-8 Sep 9.3-9.4 4 4 S 8 (2) 11-15 Sep (Mon=WedT, Tue=MonT, 13=SD) 18-22 Sep 9 (0) ST1 (Mon 21 Aug) Tut test 2 moved to this week 1 N 9.4 Recess (14-23 Sept) Tut & Prac 4 due on 18th Sept 10 (3) 25-29 Sep 10.1-10.2 S (25=PH) 11 (4) 2-6 Oct 12 (4) 9-13 Oct 13 (4) 16-20 Oct 14 (4) 15 (4) 16 (4) ST2 (Wed 4 Oct) 5 5 S 11.1, 11.3, 11.4 5 5 S 6 6 *Trial Practical 12.1-12.3 Test/Assignment Practical Test (Fri 27 Nov) 30 Oct-3 Nov ST3 (Mon 30 Oct) 23-27 Oct 6-10 Nov 10.3-10.5 Sick Practical Test (Wed 1 Nov) No tests this weekonly Tutorial 8 (optional) 3 S 12.4-12.6 7 S 13.1-13.3 7 N 14.1-14.2 8 N 15 Nov (Preliminary date) Exam 15h00-18h00 * PH=Public Holiday, SD=Spring Day, MonT= Monday Timetable, WedT= Wednesday Timetable ** All dates are provisional and subject to change. *** Lecturer in charge: N=Dr Najmeh Rad, S=Dr Seite Makgai 4 © 2023 University of Pretoria: Adapted for NAS 2. Administrative information 2.1 Contact details Lecturers and Tutors Name Office Contact Module coordinator & Lecturer Dr Seite Makgai IT 6-12 - wst121stats@gmail.com Lecturer Dr Najmeh Rad IT 5-27 Ms Ramadimetje Leshilo Tutors Mr Lizo Sanqela Graduate Centre 1-66 - During Tutorial and Practical sessions and via the Discussion boards. Other Support Building and room number Name Faculty Student Advisor* Mpho Mmadi Subject librarian Katlego Aphane Maths Building, Room 1-29 Merensky library, level 5, office 5-4 Office Telephone number Email address 012 420 6740 mpho.mmadi@up.ac.za 012 420 4791 katlego.aphane@up.ac.za * Your Faculty Student Advisor can advise you on goal-setting, adjustment to university life, time management, study methods, stress management and career exploration. Book an individual consultation or attend a workshop. For other support services see Section 5. Click HERE for contact details for other NAS FSAs. For more info on the Department of Statistics, visit us on the internet: https://www.up.ac.za/statistics 5 © 2023 University of Pretoria: Adapted for NAS 2.2 Timetable Scheduled session Day Time Venue Lecture 1 Monday 14:30 -15:20 Thuto 1-2 Lecture 2 Wednesday 07:30-8:20 Pre-recorded video i.e. no live lecture Lecture 3 Thursday 14:30-15:20 Thuto 1-2 Lecture 4 Friday 10:30-11:20 Thuto 1-2 Tutorial group 1 Monday 10:30-12:20 Te Water hall Tutorial group 2 Wednesday 14:30-16:20 IT 2-23 Practicals Practicals Monday Wednesday 12:30-13:20 16:30-17:20 Informatorium Fill the labs in this order: 1. Orange 2. Blue 3 3. Blue 2 4. Blue 1 Informatorium Fill the labs in this order: 1. Red 2. Grey 3. Purple 4. Blue 1 5. Blue 2 The course consists of: ● FOUR lecture periods per week (3 in-person, and 1 pre-recorded lecture on Wednesdays). The lectures will be marked as Lecture 1, Lecture 2, Lecture 3 and Lecture 4 in the weekly schedule. The lecturer will indicate the material that will be covered in this session in the Weekly Work Scheduled. ● ONE tutorial session per week (in-person). A worksheet with individual assignments will be published on ClickUP weekly. Your completed assignment and answers must be submitted on ClickUP. Memos will be published on ClickUP. You will have one or two weeks to complete your tutorial assignment and submit your answers on ClickUP. The submission link opens on Monday at 7am of the first week of the assignment and closes at 7am on Monday of the week when the next assignment is released. The purpose of these assignments is to give you better insight into the subject-matter treated in class and a better understanding of applications of the subject in order to improve self-tuition. 6 © 2023 University of Pretoria: Adapted for NAS ● ONE practical session per week (in-person). You must fill the labs according to the order given in the study guide. In the practical sessions, using the programming language R/RStudio, you will be given the opportunity to practically apply theoretical concepts covered during lectures. A worksheet with a practical assignment will be published on ClickUP. Unless otherwise stated in your assignment instructions, you will have two submissions for each Practical. The first is the submission of your R script. You will be able to submit your script as many times as you like and will receive immediate feedback on this. The aim of this is to give you the opportunity to correct your code and make coding less intimidating. Once you are satisfied that your code is correct, you can move on to the results/interpretation submission. You will have only one opportunity for this submission and will not receive immediate feedback. Your R script as well as results/interpretations must be uploaded to Gradescope. To access Gradescope, please use the link provided on ClickUP → Practicals. You will have either one or two weeks to complete your practical and submit your code and results on ClickUP. The submission link opens on Monday at 7am of the first week of the assignment and closes at 7am on Monday of the week when the new assignment is released. Sick notes are NOT accepted for missed • • • tutorial/practical submissions, ClickUP assessments or tutorial tests and there will not be additional opportunities or supplementary assessments to make up for them or to improve marks. In order to accommodate cases where a student may miss an assessment, only selected assessments are counted towards the semester mark: Only the best 6 tutorials, the best 2 tutorial tests and the best 4 practical assignments (excluding Practical 0, and including the Trial Prac test) will count towards your semester mark. Note that this does not apply to the semester tests and practical test. ALL semester tests and the practical test are compulsory and count towards your semester mark. If you miss any semester test or the practical test, you must apply for the relevant sick test. (See section 3.3.1) 2.3 Study material and purchases Prescribed Book (e-book) (DB): Title: Modern Mathematical Statistics with Applications Authors: Devore, J.L.,Berk,K. N. Edition: 2nd (2012) The textbook is available on the Library website. Only selected parts of the textbook will be covered in this module. See Study Themes and Units in this guide for detail. 7 © 2023 University of Pretoria: Adapted for NAS All students are expected to use their own calculators. Scientific calculators with facilities for regression and correlation are recommended. No programmable calculators allowed. R and RStudio should be downloaded and installed on your computer. Students who are unable to install this software can make use of Google Collaboratory. Details of these can be found on ClickUP in Course Materials → Practicals → Practical 0. 3. Assessments 3.1 Key T Assessment plan Assessment type Assessment venue/platfor m About Due date Weight Selected Mondays at 7am*** Selected Mondays at 7am*** 21 Aug* 4 Oct* 30 Oct* 27 Oct* 37.5 or 37.5 or 37.5 or 10 Tutorials ClickUP P Practicals ClickUP ST1 ST2 ST3 PT Sick PT Semester test 1 Semester test 2 Semester test 3 Practical test Written Written Written Lab Exercises based on each chapter Practical application of theory covered each chapter Chapter 6, 7** Chapter 8, 9** Chapter 10, 11** All Practicals SICK Practical Test Lab All Practicals 1 Nov* 10 TT Tutorial Tests Written Tutorial test 1: 6.1-6.2** Tutorial test 2: 8** Tutorial test 3: 10** During the tutorial Classes* 5 5 5 100 * Preliminary dates, subject to change ** Subject to change *** See Section 2.2 for details ****Weight is according to the number of semester tests missed ● Semester Tests: Three semester tests will be written. All tests will be written on campus – all 3 tests are compulsory. The best 2 out of the 3 semester tests will be taken. ● Practical test: A final practical test (in R) based on the practical assignments will be written at the end of the semester and submitted to Gradescope. ● Tutorial tests: Three tutorial tests will be written during the Monday/Wednesday tutorial sessions. Test memos/explanations will be published on ClickUP. If you have queries about marks or the allocation of marks first check the memo and send queries within the specified time. Please send an email to wst121stats@gmail.com along with a clear explanation of your query. Your query will be checked and your mark will be changed if necessary. You will have until one week after the marks are published to send queries. After this time no marks will be adjusted. Please note that due to capacity and time of the assessments, we will no longer have a sick semester test, but we will consider the best 2 out of the 3 semester tests. If a student misses any one of the semester tests, he/she must write the other semester tests to increase their chance of getting a good semester mark. 8 © 2023 University of Pretoria: Adapted for NAS 3.2 Semester mark calculation Semester marks are calculated in the following manner (refer to keys given in the above table in column 2): 1. Convert all your marks to percentages. 2. Select the best 2 tutorial tests, the best 6 tutorials and the best 4 practical assignments (excluding Practical 0, but including the Trial Prac test/assignment) will count towards your semester mark. 3. Your semester mark is then calculated according to the following formula: Semester mark= (0.05 x T)+(0.05 x P)+(0.375 x ST1)+(0.375 x ST2 or 0.375 x ST3)+(0.1 x PT)+(0.05 x TT) Example: 1. Suppose your tutorial marks (in %) were 45, 75, 65, 60, 55, 70, 84, 90 then only the best 6 highlighted marks will count towards your semester mark. Therefore, T = (75 + 65 + 60 + 70 + 84 + 90)/6 = 74 2. Repeat step 2 for best 4 Practicals (P) and best 2 Tutorial Tests (TT) and best 2 Semester tests (ST). 3. Final calculation example: Example: Tuts: 75% Pracs: 77% ST1:60% ST2: 75% ST3:80% PT:65% TT: 90% Semester mark = (0.05 x 75)+(0.05 x 77)+(0.375 x 75)+(0.375 x 8.)+(0.10 x 65)+ (0.05 × 90) ≈ 76.725% Note: A student must obtain a semester mark of at least 40% in WST121 to be allowed to write the final examination (exam entrance). No exceptions will be made. Semester marks are displayed on ClickUP shortly before the official closing of lectures at the end of the semester, i.e. 10 November 2023. 3.3 Assessment policy A student must obtain a semester mark of at least 40% in WST121 to be allowed to write the examination. Pre-requisite: A student needs to obtain a final mark of at least 50% in WST111 for admission to WST121. As of the year 2023, GS does not apply to this module, i.e. your final WST 111 mark MUST BE at least 50% (not 40%) to qualify for WST 121. The final mark (FM) is compiled using the semester mark (SM) and the examination mark (EM). The SM and EM either count 50% each, or the SM counts 40% and the EM 60%, depending on which set of weights is most beneficial to the student. The 50/50 and 40/60 weightings will be calculated for each student and the combination which gives the highest mark will be the student’s final mark. 9 © 2023 University of Pretoria: Adapted for NAS Example 1: (50 SM & 50 EM) SM: 90% EM: 70% Final mark = 0.5 SM + 0.5 EM = 0.5 90 + 0.5 70 = 80% Example 2: (40 SM & 60 EM) SM: 70% EM: 90% Final mark = 0.4 SM + 0.6 EM = 0.4 70 + 0.6 90 = 82% A student must achieve at least 40% in the exam- even if you have a very good semester mark (for subminimum purposes). A supplementary exam must be written if your FM is above 50% but your EM is below 40%. Students with a final mark of 40% to 49% qualify for a supplementary examination. 3.3.1 Procedure to be followed when a semester test cannot be written ● ● ● ● ● ● In terms of the regulations of the University of Pretoria, if there is a valid reason for not being able to write a semester test, the student must notify the lecturer beforehand or within three (3) working days of the date of the test that was not written. A medical certificate cannot be submitted after a student has written a test. Note, once a test has been started it is considered to have been written. In all cases, the application form in Annexure 1 (at the end of the study guide) must be submitted along with supporting documentation. Clearly indicate the course (WST121), your student number, surname and initials as well as a contact number. Documentation must be submitted via email to the wst121stats@gmail.com address. In those situations where a certificate from a medical practitioner is the supporting documentation: o Only original certificates issued by medical practitioners registered with the Council for Health Professions and the Allied Health Professions Council of SA will be accepted. o The certificate from the medical practitioner must be dated on or before the date of the test. Certificates dated after this date will not be accepted. o The certificate must clearly specify the period for which the student is booked off. o Any certificate from a medical practitioner stating “I have been informed that. ” or similar will not be accepted or considered. o Furthermore, a certificate from a medical practitioner will not be accepted or considered if it merely states that the student appeared ill or declared him/herself unfit. o The validity of the certificate from the medical practitioner will be verified directly with that practitioner. In those situations where a certificate from a medical practitioner is not the supporting documentation: o A sworn affidavit (original copy) must be submitted together with other original, suitable and verifiable documentation. In the event of a funeral, a copy of the death certificate of the deceased or other substantiating evidence is required together with an explanation of the relationship between the student and the deceased. In the event of load shedding, proof of the student’s address and proof that there was load shedding taking place in the area must be supplied. 10 © 2023 University of Pretoria: Adapted for NAS o ● ● ● ● ● ● The validity of the affidavit and the other supporting documentation will be verified with the corresponding authorities and persons concerned. Students not complying with these regulations do not have any right to be otherwise accommodated or to be given an alternative opportunity to write the test. The worn excuses of having overslept or read the timetable incorrectly will not be accepted. So-called sick tests are not granted automatically – all relevant authorities and persons will be consulted to establish the merit of the case. False medical certificates or sworn affidavits will be interpreted as unethical and fraudulent. Any unethical or fraudulent behaviour will be reported to the Faculty and disciplinary steps will be taken. If a test in WST121 is scheduled at the same date and time as a test in another subject, the student must notify the lecturer at least 1 week before the test date. Examination: In case you could not write the exam, you should consult the administration of the Faculty of Natural and Agricultural Sciences - no medical certificates or affidavits from students may be accepted by the departments (Statistics 1-Stop, lecturers or Head of Department) with respect to the exam. Also, no application for a sick exam that is submitted to Faculty after 3 days of the exam will be accepted, even if a student handed it in with the lecturer or Head of Department. THE DISHONEST MISSING OF A TEST AS WELL AS DISHONESTY DURING THE WRITING OF TESTS WILL NOT BE TOLERATED UNDER ANY CIRCUMSTANCES. ALL IRREGULARITIES WILL BE SEEN IN A SERIOUS LIGHT AND WILL BE REPORTED TO THE REGISTRAR (ACADEMIC). The University of Pretoria commits itself to produce academic work of integrity. You have affirmed, by signing the integrity statement on ClickUP, that you are aware of and have read the Rules and Policies of the University, more specifically the Disciplinary Procedure and the Tests and Examinations Rules, which prohibit any unethical, dishonest or improper conduct during tests, assignments, examinations and/or any other forms of assessment. You are aware that no student or any other person may assist or attempt to assist another student, or obtain help, or attempt to obtain help from another student or any other person during tests, assessments, assignments, examinations and/or any other forms of assessment. The University encourages students to familiarise themselves with the Disciplinary Code for Students, contained in the UP General Rules and Regulations 3.4 Plagiarism Plagiarism is a serious form of academic misconduct. It involves both appropriating someone else’s work and passing it off as one’s own work afterwards. Thus, you commit plagiarism when you present someone else's written or creative work (words, images, ideas, opinions, discoveries, artwork, music, recordings, computer-generated work, etc.) as your own. Only hand in your own original work. Indicate precisely and accurately when you have used information provided by someone else. Referencing must be done in accordance with a recognised system. Indicate whether you have downloaded information from the Internet. For more details, visit the library’s website: http://www.library.up.ac.za/plagiarism/index.htm. 11 © 2023 University of Pretoria: Adapted for NAS 3.5 Programme/Departmental/Module rules, requirements and guidelines The WST121 module is at first year level. A WST111 FINAL MARK (combined semester and examination mark) of at least 50% is the prerequisite for WST121. The two modules (WST111 and WST121) are prerequisites for WST211. Only students who passed WST111 and WST121 (at least 50% in both cases) will be allowed to continue with Mathematical Statistics at a second year level. The practical component of the WST121 module utilises the programming language R for practical applications and illustration of theoretical concepts. If you are registered in the Actuarial programme, please note: In order to qualify for the actuarial exemption, you must complete WST111, WST121 (first year) as well as WST211, WST221 (second year) under the following conditions: ● You must achieve an average mark of 60% across the four subjects’ examination papers. ● You must score a subminimum of 55% in each examination paper. Because you can score a maximum of 50% in a supplementary examination, it does not count. Note, even if you miss the exemption requirements, but still pass all your modules, you will still qualify to get the degree. If you miss this exemption, please note that you can still obtain it by writing one of the Actuarial board exams (see https://www.actuarialsociety.org.za/ for more information). 12 © 2023 University of Pretoria: Adapted for NAS 3.6 Code of conduct We are not only facilitating learning in a module, we are also preparing you for the world of work. We expect you to adhere to the code of conduct as spelled out in the Escalation policy of UP. 3.6.1 Communication via email (wst121stats@gmail.com) When you send an email to the lecturer, you have to use a respectful tone and include all the following aspects: ● A clear and explanatory heading (e.g. “Sick note for ST1”) in the subject line; ● Your full name, surname and student number at the end of the mail; ● Short and clear message. ● Harassment/violent/abusive messages sent via email will not be tolerated and will be escalated to Faculty for disciplinary action. 3.6.2 Compliments and complaints You are more than welcome to express your appreciation to your lecturer or tutor and supply feedback about aspects of the course that you enjoy and find valuable. If you have a query or complaint, you have to submit it in writing with specifics of the issue or the nature of the complaint. It is imperative that you follow the procedure outlined below in order to resolve your issues: 1. Consult the lecturer concerned about your complaint/concerns. If the matter has not been resolved, 2. consult the class representative (The primary function of the Class Representative is to serve as a two-way communication channel between the class and the lecturer). If the matter has not been resolved, 3. consult the module co-ordinator (large modules with multiple lecturers) If the matter has not been resolved, 4. consult the Head of Department (cc the module co-ordinator) If the matter has still not been resolved, 5. consult with the Dean of the Faculty (cc the Head of the Department) Other University Policies and Regulations: https://www.up.ac.za/article/2754069/up-policies-andother-important-documents 13 © 2023 University of Pretoria: Adapted for NAS 4 Module information 4.1 Purpose of the module The goal of the WST111 module was to present a solid undergraduate foundation in statistical theory while the WST121 module provides an indication of the relevance and importance of the theory in solving practical problems in the real world. Topics that are covered include the following: Sampling distributions. Statistical inference: Point and interval estimation. Hypothesis testing with applications in one and two-sample cases. Linear models and estimation by least squares. Analysis of variance. Introductory categorical data analysis. Distribution-free testing methods. Identification, use, evaluation and interpretation of statistical computer packages and statistical techniques. 4.2 Module outcomes The student must be able to use the sampling distributions such as the normal distribution, the 𝜒2distribution, the 𝑡-distribution and the 𝐹-distribution to calculate probabilities associated with sample statistics. The student must be able to understand the importance of estimation and the difference between the point estimation and interval estimation of a specific population parameter. The student must be able to understand the importance of hypothesis testing and to be able to make scientifically accountable decisions concerning the population mean, 𝜇, the population proportion, 𝑝, the population variance, 𝜎2, the difference between two population means, 𝜇1– 𝜇2, the difference between two population proportions, 𝑝1– 𝑝2, and the equality of two population variances, 𝜎2 = 𝜎2. 1 2 The student must be able to use the method of least squares to fit a linear model to an experimental response. The student must be able to solve inferential problems associated with the linear statistical model such as estimation and tests of hypotheses relating to the model parameters. The student must be able to use the technique of analysis of variance to compare the means of more than two populations. The student must be able to identify a multinomial experiment and calculate cell probabilities associated with the experiment. The student must be able to use nonparametric techniques to analyse data where response measurements are difficult to quantify or assumptions underlying standard methodology are not met. The student must be able to identify the nature of the data in a specific problem and on the basis of that decide on an appropriate analysis technique. 4.3 Articulation with other modules in the programme The WST121 module is typically included in BSc programmes such as BSc in Actuarial & Financial Mathematics, Mathematical Statistics, Mathematics, Physics, IT or Computer Science and BCom programmes such as BCom degrees in Statistics or Econometrics. 14 © 2023 University of Pretoria: Adapted for NAS 4.4 Module structure Linear Models Sampling distributions Estimation Hypothesis testing Analysis of Variance Analysis of Categorical Data Alternative approaches 4.5 Learning presumed to be in place A WST111 FINAL MARK (combined semester and examination mark) of at least 50% is the prerequisite for WST121. 4.6 Credit map and notional hours This module carries a weighting of 16 credits, indicating that a student should spend an average of 160 hours to master the required skills (including time spent preparing for tests and examinations). This means that you should devote an average of 12 hours of study time per week to this module. The scheduled contact time is approximately five hours per week, which means that at least another 7 hours per week of own study time should be devoted to the module. The number of credits allocated to a module give an indication of the volume of learning required for the completion of that module and is based on the concept of notional hours. Given that this module carries a weighting of 16 credits, it follows that you should spend an average of 10x16 hours of study in total on the module (1 credit = 10 notional hours). This includes time for lectures, assignments, tests and exams. This means that you should spend approximately 160 hours/14 week = 12 hours per week: Independent Work* Lectures/ Live Tutorial & Textbook Revision Practical Tutorials exercises Practical Sessions 5 hours 3.5 hours 1 hour 1.5 hours 1 hour * Values are estimates. Distribution of hours will vary per student. 15 © 2023 University of Pretoria: Adapted for NAS 4.7 Units Unit: Statistics and Sampling Distributions Statistics and their distributions (DB p.285—294, Example 6.3 excluded) You must be able to: ● define a statistic ● define and understand the concept of a sampling distribution ● define a random sample ● derive sampling distributions using probability rules ● use simulation experiments to identify: o the general shape of the sampling distribution of a sample mean when sampling from normal and non-normal distributions o the effect of the sample size and number of repetitions on the sampling distribution of the sample mean Key concepts: statistic, sampling distribution, inference, goodness of the estimate, sample mean, sample variance, sample size. The distribution of the sample mean (DB p.296-302) You must be able to: ● identify the relationship between the sampling distribution of the sample mean parameters and population parameters ● identify the importance of the normal distribution in statistical inference regarding 𝜇 (with 𝜎2 known) and regarding 𝑇0 ● use the distribution and parameter values of the sample mean and total obtained from a normal distribution ● know and use the central limit theorem Key concepts: expected value of the sample mean, variance of the sample mean, expected value of the sample total, variance of the sample total. The mean, variance and MGF for several variables (DB p.306-309, p. 311-312) (Proof, Proposition, Example 6.16 on p.310 excluded) You must be able to: ● define a linear combination ● give the expected value and variance of a linear combination of independent random variables ● identify the importance of the normal distribution in statistical inference regarding ● 𝜇1 − 𝜇2 (with n1 and n2 very large) ● give the MGF of a linear combination of independent random variables Key concepts: linear combination, independent variables, difference between two variables, momentgenerating function for linear combinations, case of normal random variables. Distributions based on a normal random sample (DB p. 315-325, Proof p.321 excluded, Moments of 𝑡 excluded) You must be able to: ● give the distribution of the sum of squares of independent, standard normal variables ● identify the importance of the 𝜒2-distribution in statistical inference regarding 𝜎2 ● identify the distribution of a function of the sample variance 16 © 2023 University of Pretoria: Adapted for NAS ● ● ● describe the relation between the sample mean and sample variance identify the relation between the t-distribution, the standard normal and 𝜒2-distribution use the normal distribution, the 𝜒2-distribution, the t-distribution and the F-distribution to calculate probability expressions in terms of statistics with their associated sampling distributions. Key concepts: distributions based on a normal random sample, inference, goodness of the estimate, sample mean, sample variance, sample size, t-distribution, normal distribution, 𝜒2-distribution, Fdistribution. Unit: Point estimation General concepts and criteria (DB p.331-345) The Bootstrap excluded) You must be able to: ● define a point estimate and point estimator ● define and calculate the mean square error of a point estimator ● define an unbiased estimator ● define and calculate the standard error of a point estimate Key concepts: parameters, point estimate, interval estimate, estimator, point estimator, unbiased estimator, bias, mean square error. Section 7.2, Section 7.3, Section 7.4 excluded Some common unbiased point estimators (Additional material) You must be able to: ● give and use the expected values and standard errors of common estimators Unit: Statistical intervals based on a single sample Basic properties of confidence intervals (DB p.382-390) You must be able to: ● calculate the sample size required for a certain interval width ● calculate the bound on the error of estimation ● derive, calculate and interpret a confidence interval Key concepts: interval estimator, confidence interval, upper and lower confidence limit, confidence coefficient Large-sample confidence intervals for a population mean and proportion (DB p.391-399) You must be able to: ● derive, calculate and interpret large-sample confidence intervals for the population mean and proportion ● identify the effect of the sample size, as well as the effect of the confidence coefficient on the size of a confidence interval ● specify the assumptions required to construct such large-sample confidence intervals. Key concepts: approximately normal sampling distribution, one-sided confidence limits, upper bound, lower bound, confidence coefficient, target parameter 17 © 2023 University of Pretoria: Adapted for NAS Intervals based on a normal population distribution (DB p.401-406) You must be able to: ● derive, calculate and interpret confidence intervals for the population mean with unknown variance ● specify the assumptions required to construct such an interval ● derive a prediction interval for a single observation Key concepts: t-distribution, confidence interval, prediction interval Confidence intervals for the variance and standard deviation of a normal population (DB p.409-410) (Section 8.5 excluded) You must be able to: ● derive, calculate and interpret confidence intervals for the population variance and standard deviation ● specify the assumptions required to construct such an interval Key concepts: confidence interval, confidence level, normality, 𝜒2-distribution Unit: Tests of hypotheses based on a single sample Hypotheses and test procedures (DB p.425-434) You must be able to: ● name the elements of a test procedure ● define and formulate both the null and the alternative hypothesis for a specific problem ● define a type I error ● define a type II error ● understand the relation between the risks 𝛼 and 𝛽. Key concepts: research hypothesis, alternative hypothesis, null hypothesis, impossible vs improbable, test statistic, rejection region, risk, type I error, type II error, probability of error, 𝛼, 𝛽. Tests about a population mean (DB p.436-447) You must be able to: ● identify and apply all three cases of the tests about a population mean ● determine the sample size needed based on 𝛼 and 𝛽 Key concepts: upper-tail and lower-tail alternative, two-tailed alternative, one-tail testing, two-tailed testing, upper-tail RR, lower-tail RR, two-tailed RR, test statistic, rejection region, sample size, type II error probability,𝛼,𝛽. Tests concerning the population proportion (DB p.450-453) You must be able to: ● identify and apply a large-sample test ● calculate 𝛽 ● determine the sample size required for a given 𝛼 and 𝛽 ● identify and apply a small-sample test Key concepts: upper-tail and lower-tail alternative, two-tailed alternative, one-tail testing, two-tailed testing, upper-tail RR, lower-tail RR, two-tailed RR, test statistic, rejection region. 18 © 2023 University of Pretoria: Adapted for NAS Tests concerning the population variance (Additional material) You must be able to: ● apply a test procedure for the variance Key concepts: upper-tail and lower-tail alternative, two-tailed alternative, one-tail testing, two-tailed testing, upper-tail RR, lower-tail RR, two-tailed RR, test statistic, rejection region. p- Values (DB p.456-465) You must be able to: ● define a p-value ● make a decision regarding a hypothesis based on the p-value ● calculate the p-value for a z-test ● calculate the p-value for a t-test Key concepts: p-value, observed significance value Section 9.5 excluded. Unit: Inferences based on two samples z Tests and confidence intervals for a difference between two population means (DB p.484-495) You must be able to: ● name the assumptions required for the z-test ● derive the test statistic used to test the hypotheses for a difference in means ● apply the test procedure for normal populations with known variance ● apply the large-sample test ● identify the effect of the sample size ● calculate a confidence interval for the difference in means Key concepts: difference in means, alternative hypotheses, sample size, confidence interval The two-sample t-test and confidence interval (DB p.499-505) You must be able to: ● name the assumptions required for the t-test ● derive the test statistic used to test the hypotheses for a difference in means ● apply the t-test procedure for normal populations with unknown variance ● calculate a confidence interval for the difference in means ● name the assumptions required for the pooled t-test ● apply the pooled t-test procedure for normal populations with unknown variance Key concepts: upper-tail and lower-tail alternative, two-tailed alternative, one-tail testing, two-tailed testing, upper-tail RR, lower-tail RR, two-tailed RR, test statistic, rejection region. 19 © 2023 University of Pretoria: Adapted for NAS Analysis of paired data (DB p.509-516) You must be able to: ● name the assumptions required for the paired t-test ● apply the paired t-test procedure for paired data ● calculate a confidence interval for the difference in means for paired data Key concepts: upper-tail and lower-tail alternative, two-tailed alternative, one-tail testing, two-tailed testing, upper-tail RR, lower-tail RR, two-tailed RR, test statistic, rejection region. Inferences about two population proportions (DB p.519-525) You must be able to: ● derive and apply the test procedure to test the hypotheses for the difference in proportions for large samples ● calculate the type II error probability and sample size required ● calculate a large-sample confidence interval for the difference in proportions Key concepts: upper-tail and lower-tail alternative, two-tailed alternative, one-tail testing, two-tailed testing, upper-tail RR, lower-tail RR, two-tailed RR, test statistic, rejection region, type II error probability, sample sizes. Inferences about two population variances (DB p.527-531) You must be able to: ● apply the test procedure to test the hypotheses for the ratio of variances ● calculate p-values for the F-test ● derive and calculate a confidence interval for the ratio of variances Key concepts: upper-tail and lower-tail alternative, two-tailed alternative, one-tail testing, two-tailed testing, upper-tail RR, lower-tail RR, two-tailed RR, test statistic, rejection region, p-value. Section 10.6 excluded. Unit: Analysis of Variance Single factor ANOVA (DB p. 552-563) You must be able to: ● know the notation and assumptions required for a single factor ANOVA ● define the treatment and error sum of squares and their relationship as well as their respective distributions ● define the mean square for treatments and error ● derive a test statistic based on sum of squares for treatment and error to compare more than two population means ● perform a statistical test based on sum of squares for treatment and error to compare the means of two populations ● construct an ANOVA table ● know the effect of the violation of the assumptions Key concepts: factor, level, qualitative variable, ANOVA, total sum of squares, sum of squares for treatments, sum of squares for error, F-distribution. Section 11.2 excluded. 20 © 2023 University of Pretoria: Adapted for NAS More on single factor ANOVA (DB p. 572-573) You must be able to: ● give the alternative formulation of the single factor model Section 11.3 from middle p.573-p.580 excluded. Two-factor ANOVA with Kij=1 (DB p. 583-587) You must be able to: ● identify a two-factor ANOVA experimental situation ● know the notation and assumptions required for a two-factor ANOVA ● formulate the two-factor ANOVA model ● calculate the relevant sums of squares for the two-factor ANOVA procedure ● calculate the test statistics for the two relevant alternative hypotheses ● construct the corresponding ANOVA table Key concepts: two factors of simultaneous interest, factor A, factor B, factor levels, SST, SSA, SSB, SSE, MSA, MSB, MSE, F-ratios. Section 11.4 from p.590, Randomized Block Experiments excluded. Section 11.5 excluded. Unit: Regression and correlation The simple and multiple linear regression model (DB p.613-620,682) (Logistic regression model excluded) You must be able to: ● define a simple linear regression model ● define a multiple linear regression model ● calculate and use the expected value and variance of 𝑌 for a given 𝑥 Key concepts: deterministic, probabilistic, dependent, independent, regression line Estimating model parameters (DB p.624-636) You must be able to: ● derive and calculate least square estimators and estimates for the parameters ● estimate ● calculate and interpret the coefficient of determination Key concepts: fitted (predicted values), error sum of squares, total sum of squares, explained variation, expected value and variance of least squares estimator(s), unbiased, covariance of least squares estimators, distribution of least squares estimators. 2 Inferences about the regression coefficient β1 (DB p.640-649) (Fitting of the Logistic Regression Model excluded) You must be able to: ● derive a statistical test for 𝛽1 ● perform and interpret the results of a hypothesis test ● derive a confidence interval for β1 21 © 2023 University of Pretoria: Adapted for NAS ● construct an ANOVA table Key concepts: upper-tail RR& alternative, lower-tail RR & alternative, two-tailed RR & alternative, tdistribution, p-value, confidence interval. Inferences concerning the prediction of future y values (DB p.654-659) You must be able to: ● calculate a confidence interval for the mean value of the dependent variable when the explanatory variable has a particular value ● calculate a prediction interval for the dependent variable when the explanatory variable has a particular value. Key concepts: confidence interval, prediction interval. Correlation (DB p.662-670) You must be able to: ● calculate an estimate for the population correlation coefficient ρ ● know the properties of r ● test appropriate hypotheses regarding ρ using a t-test ● explain the relation between ρ and β1 ● test appropriate hypotheses regarding ρ using a Z-test ● derive the relation between the sample correlation coefficient and the coefficient of determination ● interpret the values of the correlation coefficient and the coefficient of determination. Key concepts: bivariate normal distribution, sample correlation coefficient , RR, alternative, coefficient of determination, explained variation. Assessing model adequacy (DB p.674-679) You must be able to: ● interpret residual plots ● recognize plots that indicate abnormality in the data suggest remedies for specific abnormalities in the data Key concepts: residual plot, standardized residuals, nonlinear relationship, non-constant variance, discrepant observation, observation with large influence, dependence in errors, variable omitted. Section 12.7 from Estimating Parameters excluded Section 12.8 excluded Unit: Goodness-of-fit tests and categorical data analysis Goodness-of-fit tests when the category probabilities are completely specified (DB p. 723-730) You must be able to: ● identify experiments where measurements are qualitative rather than quantitative ● apply a 𝜒2 test procedure to test an hypothesis ● know the relationship between the 𝜒2-test and the z-test Key concepts: qualitative or categorical measurements, observed counts, expected counts, number of degrees of freedom. 22 © 2023 University of Pretoria: Adapted for NAS Goodness-of-fit tests for composite hypotheses (DB Section 13.2 replaced by additional material) You must be able to: ● test a hypothesis concerning specified cell probabilities ● test whether a specific model for a population distribution fits the sample data Key concepts: specified cell probabilities, goodness-of-fit test. Two-way Contingency tables (DB p. 744-749) (Excluded from Ordinal Factor & Logistic Regression) You must be able to: ● estimate row and column probabilities in order to estimate expected cell frequencies under independence ● perform a statistical test to determine whether two classification variables are homogeneous ● perform a statistical test to determine whether two classification variables are dependent. Key concepts: dependency/contingency between two classification criteria, contingency table, row probabilities, column probabilities, degrees of freedom, independence, expected cell frequencies, collapsed marginal tables. Unit: Alternative approaches to inference The Wilcoxon signed-rank test (DB p. 758-763) You must be able to: ● perform the Wilcoxon signed rank test to test a hypothesis concerning the mean ● perform the Wilcoxon signed rank test to test a hypothesis concerning the mean for paired data ● give the assumptions required to perform the Wilcoxon signed rank test ● determine the values for which the null hypothesis should be rejected for a given significance level ● calculate the p-value for a given value of the test statistic ● adjust the procedure in the presence of ties Key concepts: absolute value of differences, ranks, ties, Wilcoxon signed rank test, two-tailed test, onetailed test, test statistic, rejection region, critical value, attained significance level, approximately normally distributed. The Wilcoxon rank-sum test (DB p. 766-769) You must be able to: ● understand how the rank sums of two samples can be used to determine whether two population distributions differ in location ● calculate the test statistic ● perform the Wilcoxon rank-sum test to test whether two independent population distributions differ in location ● formulate the appropriate null and alternative hypothesis for two-tailed or one-tailed testing ● determine the rejection region for any given alternative 23 © 2023 University of Pretoria: Adapted for NAS Key concepts: compare two populations, independent random samples, rank-sum test, rank combined set of observations, ties, average ranks, alternative hypothesis, distribution shifted to the right/left, one-tailed, two-tailed, rejection region. Section 14.3, 14.4 excluded 5 Support services Please download a QR code reader on your cellphone. To download a QR code reader, open your mobile app store (App Store, Google Play or Windows Marketplace) and search for QR code readers. E-learning support ● ● ● Report a problem you experience to the Student Help Desk on your campus. Call 012 420 3837. Email studenthelp@up.ac.za Other support services: FLY@UP: The Finish Line is Yours Disability Unit Student Counselling Unit ● Think carefully before dropping modules (after the closing date for amendments or cancellation of modules). ● Make responsible choices with your time and work consistently. ● Aim for a good semester mark. Don’t rely on the examination to pass. 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I confirm that I have read and understood the matters relating to the submission of excuses/apologies as contained in the WST121 Study Guide under Section 3.3.1 I declare that this is a bona fide application and that the medical certificate and/or supporting documents attached are true. ................................ SIGNATURE .................... DATE 26 © 2023 University of Pretoria: Adapted for NAS