EDUC 203 ADVANCED STATISTICAL METHODS • Floricel V. Ulat, Ph D • 05Feb2022 CHAPTER 1 INTRODUCTION “STATISTICS is the most important science in the whole world; for upon it depends the practical application of every science and every art; the one science essential to all political and social administration, all education, all organization based on experience, for it only gives results of our experience.” -Florence Nightingale STATISTICS originated from Latin word status, which means “state.” the term itself became popular in the 18th century its original definition was “the science dealing with data about the condition of a state or community” uses of statistics during biblical times: collecting data on taxes population count poultry and livestock agricultural products, labor and resources from every citizen of the land STATISTICS The use of statistics in government is still evident these days: • Countries now regularly compute for various socioeconomic indicators such as: - Consumer Price Index (CPI) - Gross National Product (GNP) - Gross Domestic Product (GDP) - Birth rates and mortality rates, - unemployment rates, - literacy rates, and - monetary exchange rates STATISTICS • At present, the government is not the only major user of statistics • it expanded to almost every field of study • it provides answers to research questions, helps in decision making • and aids in the process of choosing appropriate actions to be taken through the analysis of available information. * Medicine * Business Sector * Education * Tourism Industry, Sports and etc. BASIC CONCEPTS OF STATISTICS STATISTICS – is the branch of science that deals with the collection, presentation, organization, analysis and interpretation of data. POPULATION – the collection of all elements under consideration in a statistical inquiry. SAMPLE – is a subset of population. Sample Population Relationship Between the Population and Sample The elements of population can be • individuals, objects, animals, geographic areas and so on • Examples of populations under study: 1. 2. 3. 4. 5. 6. Set of Farmers in Laguna Bay Set of Public or Private School Teachers Set of Fluorescent Bulbs manufactured for a month Set of mango trees in a certain area Set of Fishponds in Binangonan Set of Rural health units in Rizal • needs to have at least one of the characteristics or attributes of the elements of the population VARIABLE – is a characteristic or attribute of the elements in a collection that can assume different values for the different elements. OBSERVATION – is a realized value of a variable. DATA – is the collection of observations. Examples: Variable 1. Sex of a students 2. Employment Status 3. Monthly Income of a Person in Pesos 4. Height of Basketball players Possible Observations Male, Female Temporary, Permanent, Contractual i>0 h > 0 cms. Exercise 1 Identify the population under study and variable/s of interest. 1. The Office of Admissions is studying the relationship between the score in the entrance examination during application and the general weighted average (GWA) upon graduation among graduates of the university from 2015 to 2018. 2. The research division of a certain pharmaceutical company is investing the effectiveness of a new diet pill in reducing weight on the female adults. 3. The Department of Health is interested in determining the percentage of children below 12 years old infected by the Hepatitis B virus in Rizal 2017 4. A researcher from LGU wants to determine the awareness of the residents of a certain barangay on the implemented projects PARAMETER – is a summary measure describing a specific characteristic of the population. STATISTIC - is a summary measure describing a specific characteristic of the sample. PROPORTION – is the quotient obtained in dividing the magnitude of a part by the magnitude of the whole. Example: * 28 out of 35 students own a cellphone in a class * among 10 students, 7 own a cellphone Exercise 2 1. A doctor claims that these tablespoons of pure virgin coconut oil daily can reduce weight. To test the doctor’s claim, a researcher studied two groups of 25 women aged 35 to 40 years with weights between 130 to 140 pounds. He administered the three tablespoons of pure virgin coconut oil daily for a period of three months to one group of women only. After three months, he weighted the two groups of women. a) Describe the two populations of interest. b) What are the two samples? 2. Mr Donato Chan, a candidate for Vice-Mayor in Orion, Bataan, wants to find out if there is a need to intensify his campaign efforts against his opponents. He requested the services of a group of students to interview 1,000 of the 3,000 registered voters of Orion, Bataan. The survey results showed that 75% of the 1,000 in the sample will vote for him as Vice-Mayor. a) Identify the population and the sample b) Identify the variable of interest c) Identify the Parameter and the Statistic 3.The average weekly allowance of students last year at a private high school was P600.00 per week, based on an enrollment of 1,080 students. The grade 9 students who did not have this information interviewed 50 students and found their average weekly allowance last year to be P550.00 a) Identify the population and the sample b) Identify the variable of interest c) Identify the Parameter and the Statistic FIELDS OF STATISTICS 2 major fields of Statistics 1. Applied Statistics – is concerned with the procedures and techniques used in the collection, presentation, organization, analysis and interpretation of data. 2 Major areas of Interest of Applied Statistics: a. Descriptive Statistics – includes all the techniques used in organizing, summarizing and presenting the data on hand. b. Inferential Statistics - includes all the techniques used in analyzing the sample data that will lead to generalizations about a population from which the sample came from. FIELDS OF STATISTICS 2. Theoretical or Mathematical Statistics is concerned with the development of the mathematical foundations used in applied statistics. • Establish new theories that will validate the use of new statistical methods or modifications of existing statistical methods in solving problems that are more complex. Some illustrations of the applications of Descriptive Statistics 1. Daily Sales performance for a product for the previous year, draw a line chart or column chart to emphasize the upward/downward of the series and calculate a quantity index per quarter to compare the sales by quarter for the previous year. 2. Compare the total area of Watershed Forest Reserves in Regions IV and VIII for a specified period, cover all the provinces in Regions IV and VIII then measure the area of each one of the watershed forest reserve in both regions. It can be interpreted using horizontal bar chart or computing for the ratios. 3. The PAGASA measures daily amount of rainfall in millimeters. It computes the average daily amount of rainfall every month for the past years. Some examples of the applications of Inferential Statistics 1. To examine the performance of the country’s financial system to arrive at conclusions that apply to the entire economy using the data gathered from a sample of companies or business in the country. 2. Determine if reforestation is effective, take a representative portion of denuded forests and draw conclusions about the effect of reforestation on all denuded forests. STEPS IN A STATISTICAL INQUIRY STATISTICAL INQUIRY - is a designed research that provides information needed to solve a research problem. Partial List of General Research Objectives that can accomplish by performing a Statistical Inquiry: 1. Identify different groups of interrelated variables under study. 2. Compare the characteristics of the elements in the different subgroups in the population through contrasts of their respective summary measures. 3. Determine the nature and relationship among the different variables of interest. 4. Predict the value of a variable based upon its relationship with another variable 5. Forecast future values of a variable using a sequence of observation on the same variable taken over time. STEPS IN A STATISTICAL INQUIRY Regardless of the complexity of the research problems, the following basic steps in performing statistical inquiry: 1. Identify the problem 2. Plan the Study 3. Collect the data 4. Explore the data 5. Analyze data and interpret the result 6. Present the results STEP 1: IDENTIFY THE PROBLEM • Define and state the problem in a clear manner. In this step establish the heart of the whole research process. • A detailed review of literature is necessary in this stage. • Provides insights on the feasibility of pursuing the problem • Must identify the specific information needed to answer the problem • Brainstorm on various issues such as importance and rationale for conducting the investigations, scope and limitations of the study. • Define the exact population of interest to delimit the scope of the study STEP 2: PLAN THE STUDY • Take all the consideration all the outputs in Step 1, the stated research problem and specific objectives • The concrete output in Step 2 is the research design (detailed methods and strategies for data collection and analysis) • Effective research design is as simple as possible, at the same time, cost-efficient. With simple RD, avoids complications and errors in its implementation. With cost-efficient RD, investigators are confident of completing the study within the allotted budget and time. • Includes the list of variables, instruments, data collection method, sampling design and methods of data analysis STEP 3: COLLECT THE DATA • Carry out the plans specified in the research design • Take extra measures to ensure the quality of the data collected • If the collected data were incomplete, outdated, inaccurate, or worse yet, fabricated, then it will be useless to proceed with data analysis • Make sure that everyone involved in data collection has a genuine appreciation for quality data. • Ways to collect data: (surveys, observation, experiments, and use of available documented data) STEP 4: EXPLORE THE DATA • Need to explore and understand the essential features of their data • Allows to determine if their data satisfy the assumptions made in the derivation of the statistical techniques • Reveals if their data exhibit peculiarities that will create problems in the analysis • Arrange the observations according to magnitude • Construct a frequency distribution which shows the number of observations in different categories • May used graphical method (usually easier to discover patterns trough visual inspection of chart) STEP 5: ANALYZE AND INTERPRET THE RESULT • Examine all the results on the table, charts, estimated summary measures and tests of hypotheses. • Need to check to meet all the specific objectives stated in Step1 • Must be able to answer the research problems and give recommendations on how can be useful in decision making • Double-check the result that contradict existing theory or the earlier hypothesis made • May propose possible explanations for the results or suggest future statistical inquiries that could help explain the inconsistency. STEP 6: PRESENT THE RESULT • Present the result in a clear and concise manner to the users of the research • Must include a discussion of the whole research process from Step 1 to 5 • The three ways of presenting the results: 1. Textual – paragraph form. 2. Tabular – showing the figures in rows and columns so that the reader can easily comprehend the points made 3. Graphical – involves placing of the data without having to look at too many figures THANK YOU!