KEY SKILLS Guidance on Assessing Application of Number Introduction The purpose of this Guidance is to assist teachers and candidates in understanding the requirements of Application of Number. Whilst this Guidance focuses upon the assessment of Part B of the Standards, it is emphasised that candidates must be wholly familiar with Part A – You Must Know How To – to ensure mastery of the techniques and knowledge needed to successfully apply these skills. This guidance should be read in conjunction with the following publication: Key Skills Standards and Guidance – Application of Number, Communication and Information Communication Technology (DELLS, CCEA and QCA) Current WJEC Key Skills Handbook for Centres WJEC and regulator’s example portfolios WJEC Candidate logbooks or centre-produced equivalents The aim of the application of number standards is to encourage candidates to develop and demonstrate their skills in interpreting information involving numbers, carrying out calculations, interpreting results and presenting findings. The standards are essentially concerned with developing and recognising the ability of candidates to select and apply numerical, graphical and related mathematical skills in ways that are appropriate to their particular context. However, they can also be used to help individuals make connection with less familiar contexts and develop their ability to progress to higher levels of competence. Techniques such as being able to measure and read scales, carry out specific calculations, or draw a particular type of diagram , are essential, but so too are the skills of application, such as interpreting information from tables, graphs or charts, selecting appropriate methods, describing what findings show, etc. Techniques and skills of application both contribute to understanding a task or problem and to deciding on the best course of action. Application of number requires candidates to interpret information presented in different graphical forms and to produce these themselves in order to present their own findings. For the purpose of the key skill, it is not necessary to distinguish between “graph” and “chart”. The basic differences between these representations and a diagram are set out in the table below Chart or Graph A representation of the relationship between variables such as categories and frequency data, or x and y coordinates. Diagram Any other graphical method of representation where scale is or is not a factor AON Guidance 26/02/2008 Pie or bar chart, histogram, pictogram, frequency polygon, frequency chart or diagram. Single or multiple line graph; scatter graph or without line of best fit. Sale drawing, plan or workshop drawing, circuit drawing, 3D representation, flow chart, critical path or network diagram, organisation chart Progression from levels 1-3 The key skills standards are designed to recognise candidates’ progression in terms of both techniques and skills of application. Progression through the levels is demonstrated by increased ability to internalise the cycle of: Collect Process Interpret With these three element corresponding to the three sections of Part B of the standards. At level 1 candidates are required to handle simple numerical and graphical information and techniques applied in the context of short activities. Calculation will usually involve only one or two steps. Much of the numerical content will be concerned with whole numbers and the use of decimals in everyday contexts (e.g. in using money or taking measurements) and the use of common units of measurement. At this level, candidates must cover each element of the Collect Process Interpret cycle, but are not required to combine them. Evidence for each element may be presented separately. At level 2 candidates are required to set their use of application of number skills in the context of at least one activity that covers all of the assessment criteria. Such an activity will give them more scope to make decisions on how to find the information they need, what calculations to use and how best to present their findings. Calculations will involve two or more steps and a more demanding range of techniques and understanding. Candidates will be expected to know how to work with numbers of any size, including addition and subtraction of factions, calculations involving area and volumes, ratio, unit conversions, percentages and scaling, as well as the use of formulae and graphs. At this level, at least one piece of work must show evidence of the whole Collect Process Interpret cycle, with other work showing evidence of ‘collect and process’ or ‘process and interpret’. At level 3 there is an increase in the complexity of activities and techniques needed. Candidates are required to be responsible for planning and carrying through their use of application of number in the context of one or more activities that cover all of the assessment criteria, including handling data from a large data set. Compared with level 2, calculations will involve several stages. Candidates need to justify their approaches and methods, in addition to presenting their findings. Calculations involve use of compound units and powers, as well as using formulae. At this level, all of the candidate’s work must show evidence of the whole data handing cycle. AON Guidance 26/02/2008 APPLICATON OF NUMBER LEVEL1 All work submitted should be in the context. Standalone exercises are acceptable, but should be in a context. N 1.1 1.2 Definition Interpret information from 2 different sources at least one source must include a table, chart, graph or diagram. Carry out and check calculations Best Practice One source MUST be graphical (a table, chart or diagram). The other should be different, e.g. questionnaire / survey; direct measurement. All sources are provided for candidates, with everyone using the same information. The purpose of the task should be set out at the beginning of the work. A series of standalone exercises lacking context. The candidates must identify with some guidance which calculations to do for themselves and explain why they are doing those calculations e.g. “I am going to add these numbers to get the total”. A worksheet that tells candidates exactly what to do and identifies the calculations needed. No explanation of what they are doing is given. Sensible rounding must be done. Candidates need to be aware of sensible levels of accuracy and present results to a given level of accuracy Inappropriate or no rounding e.g. money. Candidates unaware of level of accuracy required. Calculations should be checked. Estimation should be encouraged, reverse calculation, sense of result. Use of spreadsheets/calculations. Perform a number of different types of calculation, with and without a calculator, showing methods. Each of the following types of calculation MUST be performed AON Guidance 26/02/2008 Best Avoided Reliance on reverse calculation for all checks. No estimation or checking sense of calculation. “I have used a calculator….” Repeating of same calculations. These cover: Decimals Amounts or 1.2.1(a) Depending on one type of calculation e.g. only Fractions and Percentages sizes percentages. Simple areas and volumes Good practise would be to include more than one of these where appropriate to the task. These cover: Simple ratios Confusing presentation with calculation. Use of pie Scales or 1.2.1(b) chart is presentation not good evidence of proportion. Use of scale diagrams proportion (Unless calculation of angles and use is shown) These should be in the context of a task and scale should be noted on the diagram. These cover: Mean and Range* Handling No checking of sense of statistics and incorrect *Use of other statistics is acceptable. 1.2.1(c) Statistics calculations leading to nonsensical mean / range. Interpretation should show understanding of the meaning of these. Checking sense of mean as a mid-value is a good example of checking calculations. Interpret the results of your calculations and present your findings – in two different ways using charts or diagrams. 1.3.1 Choose suitable ways to present your findings Explain why they choose a specific type of chart, graph or diagram. This needn’t be a lengthy. Presenting the same findings numerous times. 1.3.2 Use more than one way of presenting your findings They MUST present findings in TWO DIFFERENT ways using suitable charts, graphs or diagrams. Diagrams need not be to scale. Drawing graphs for their own sake. Showing the same results several times - candidates should choose the best way to present information. 1.3 AON Guidance 26/02/2008 1.3.3 Present your findings clearly using a chart or diagram. All graphs, charts or diagrams must be labelled suitably. Diagrams, charts and graphs incorrectly labelled or not labelled at all. 1.3.4 Describe what your results tell you. Candidates must draw some conclusions from their results, graphs, diagrams, etc. These should be related to the original purpose of the task. Not interpreting graphs, etc, at all. Incorrect interpreting. AON Guidance 26/02/2008 APPLICATION OF NUMBER LEVEL 2 All work submitted MUST be relevant and in context. Standalone exercises are NOT acceptable. The portfolio must contain at least one task. One task MUST cover all criteria: Collect (N2.1), Process (N2.2 (a, b, c and d)) and Interpret (2.3) Any subsequent tasks MUST cover either Collect (N2.1) AND Process (2.2) or Process (2.2) AND Interpret (2.3) There MUST be two information sources one of which MUST be either a chart or graph. N 2.1 Definition Interpret information from a suitable source AON Guidance 26/02/2008 Best Practice Best Avoided One source MUST be a chart or graph There should to be a data set containing a suitable number of records for comparison, e.g. 20 records. There MUST be 2 sources. Sources must be clearly referenced e.g. www. Use of a chart or graph that they draw does not constitute a source. No record of source material. A table is NOT a chart The purpose of the task should be set out at the beginning of the work including an explanation of how they choose to get their information. No explanation of why they have chosen to collect the information. They can obtain relevant information from each source and explain why they need it for their task. No explanation of how the information has been collected. The candidates MUST identify which calculations to do for themselves and explain why they are doing those calculations. Carry out and check calculations Sensible rounding must be done. Candidates need to be aware of sensible levels of accuracy and present results to an appropriate level of accuracy or within given limits without guidance. Calculations should be checked. Estimation should be encouraged, reverse calculation, sense of result. Use of spreadsheets/calculations. Not all calculations need checking however a range of different checks should be shown. Perform a number of different types of multistep calculation, with and without a calculator, showing methods. 2.2 Each of the following types of calculation MUST be performed These cover: Use of, and conversion between, fractions, decimals & percentages. Conversion of measurement etc 2.2.1(a) Amounts or sizes Composite areas Volume (multi-step) These MUST involve multi-step calculations and be of a level greater than those exemplified at level 1. AON Guidance 26/02/2008 A guided task that tells the candidates what to do and how to do it. The task will identify the calculations needed. No explanation of what they are doing is given. Inappropriate or no rounding. Reliance on reverse calculation for all checks. No estimation or checking sense of calculation. Checking the same type of calculation several times. Reliance on one type of calculation to cover several criteria. Use of non multi-step calculations. E.g.: Area of simple rectangles, Calculation of a fraction or percentage of a number, e.g. ¾ of 300, 25% of 140m 2.2.1(b) 2.2.1(c) 2.2.1(d) Scales or proportion Handling Statistics Using Formulae AON Guidance 26/02/2008 These cover: Ratios Scale diagrams – calculation of length from scale diagram Scale factor/enlargement These should be in the context of a task. This could involve the drawing of a scale diagram of suitable complexity (i.e. not a simple rectangle and a scale that isn’t 1:1) These cover: Comparison of two sets of data using mean, median, mode & percentages Range* *Use of other statistics is acceptable. Interpretation should show understanding of the meaning of these. Checking sense of statistics is a good example of checking calculations. The data set should include at least 20 records. Use of formulae: In words In symbols The formula should be stated. Needs to be used within context of the task. Confusing presentation with calculation. Use of pie chart is presentation not good evidence of proportion. A scale drawing is only acceptable in the context of a task and must therefore involve either some collection (N2.1) or interpretation (N2.3). No checking of sense of statistics and incorrect calculations leading to nonsensical statistics. Not comparing two sets of data. Calculation of statistics not followed by suitable interpretation. Not stating the formula to be used. Formula not an intrinsic part of the task. 2.3 Interpret the results of your calculations and present your findings – in two different ways using charts or diagrams. Select effective Select the most appropriate method to 2.3.1 ways to present display findings. Presenting the same findings numerous times. your findings Explain their choice of methods The methods used should be the most appropriate method to display the information. Present your Inappropriate use of graphs and charts. findings clearly Choice of method should be justified. The drawing of a scale diagram without context. using a chart, graph All charts, graphs or diagrams MUST be 2.3.2 Graphs produced using ICT must also be effective and or diagram and suitably labelled. suitably labelled. describe your ICT can be used to present findings Drawing graphs for their own sake. Showing the same results methods. several times - candidates should choose the best way to present information. Use more than one Findings must be presented using at least two different methods including charts, 2.3.3 way of presenting Using only one method of presentation e.g. only using a chart. your findings graphs or diagrams. Candidates must draw conclusions from their results, graphs, diagrams, etc. Not interpreting graphs, etc, at all. These should be related to the original Incorrect interpreting. Describe what your 2.3.4 purpose of the task. Explaining all their results not selecting the most relevant results tell you. They should highlight their main findings. ones. They should either prove or disprove their Not relating finding to original purpose/hypothesis. original hypothesis. AON Guidance 26/02/2008 APPLICATION OF NUMBER LEVEL 3 All work submitted MUST be in context. Standalone exercises are NOT acceptable. The portfolio must contain one or more activities. ALL activities must cover ALL criteria: Collect (N3.1), Process (N3.2) AND Interpret (N3.3) There must be two different types of information sources, one of which MUST be a large data set (i.e. over 50 records) Multi-stage calculations differ from multi-step as follows: Multi-step / stage: a multi-step / stage calculation could involve calculation of the total of a set of data and then dividing it by the number of data items to calculate the mean. Multi-stage: the mean is calculated and the result is then used in the calculation for standard deviation. N 3.1 Definition Plan an activity and get relevant information from relevant sources. Best practise The plan should include a clear description of the activity and explain its purpose. Candidates should decide for themselves the approach to take when working on the activity. Candidates need to explain how information is obtained: questionnaire, measurement, experimentation, and graphical or written material. A clear indication of the methods chosen by the candidate justifying the choice of those methods. Best avoided A brief introduction that doesn't explain any clear purpose for the activity. Activities whose plans are intrinsic and as a result require no planning on the part of the candidate. A set of data given to the candidate that includes no reference to how or why it was collected No reference to methods chosen or why they were chosen. 3.2 Carry out and check multistage calculations AON Guidance 26/02/2008 Answers should be rounded appropriately and the level of accuracy noted. Calculations MUST involve more than one stage where results from one stage are used in a subsequent stage. Multi-stage calculations are required for each of 3.2.2 (a), (b), (c) and (d) Candidates should show their method. Inappropriate or no rounding and level of accuracy not stated. Calculations not of appropriate difficulty. 3.2.2 (a) 3.2.2 (b) 3.2.2 (c) Check methods Calculations should be checked using a range of methods as at level 2. Candidates should identify any errors in the work that are obvious and subsequently correct them. An obvious error in the work e.g. averages outside range of the data, standard deviation not sensible for the data. Amounts OR Sizes These cover: Powers and roots. Trigonometry Complex volumes and areas These must include multi-stage calculations that involve a follow through and be of a greater difficulty than those exemplified at Level 2. Simple calculations of fractions, percentages and decimals that are not multi-stage. Geometry calculations that do not involve a greater level of difficulty than those at level 2. Scales OR proportions These cover: Proportional change Use of scale, area and volume factors, e.g. doubling the dimension of a pool would increase its volume by 8 times. A scale drawing must be within the context of the task. Scale diagrams whose complexity does not exceed those described at level 2. Scale diagrams are often included for their own sake and are not really necessary within the context of the task. Handling statistics These cover: Mean & median of grouped data. Cumulative frequency – inter-quartile range. Standard deviation Histograms, frequency polygons, scatter graphs. There must be comparison using statistical methods, i.e. graphs, charts, etc or numerical statistics. Data MUST be grouped at this level and use made of the grouping e.g. putting heights into groups… 1.5 – 1.59.... Statistics not checked for plausibility. Nonsensical measures of average and spread. No comparison between sets of data. No use of grouped data. AON Guidance 26/02/2008 3.2.2 (d) Using Formulae AON Guidance 26/02/2008 These cover: Use of geometric formulae – area, volume, density etc. Rearranging geometric formulae – e.g. find height of cylinder given volume and radius Creating formulae in spreadsheet Solving of simultaneous equations Standard deviation The formulae should be stated algebraically. Results from formulae should be checked for plausibility. Formulae should involve calculations of a level 3 nature as given in 3.2.2 (a), (b) & (c) Formulas not of a complexity beyond level 2. E.g. use of area of rectangle formula. Results from formulae not checked for plausibility, especially evident with standard deviation. Interpret the results of your calculations, present your finding and justify your methods. 3.3.1 Select appropriate methods of presentation and justify your choice. 3.3.2 Present your findings effectively 3.3.3 Describe what your results tell you and whether they meet your purpose. AON Guidance 26/02/2008 Choose the best graph to: compare distributions show trends make comparisons and explain your choice – i.e. Why choose to use that graph? At least TWO DIFFERENT ways should be used for presentation of findings. Charts AND Graphs Charts AND Diagrams Graphs AND Diagrams or Graphs, Charts AND Diagrams Correct use of graphs/charts and no redundancy. All graphs should be labelled correctly. ICT may be used but candidates must check the accuracy of the presentation. Candidates explain what results tell them and refer these results back to their original plan. Candidates discuss how possible errors affected results. Graphing the same data using a variety of different methods for no apparent reason. ONE way used to present findings Charts only Graphs only Diagrams only Graphs/charts drawn and no reference made to what they display or why they were chosen. Graphs/charts labelled incorrectly or missing labels. Diagrams drawn without any purpose. Graphs drawn using ICT often are incorrectly labelled or do not follow the correct conventions. E.g. Histograms labelled as bar charts. No analysis of findings. Candidates merely state results rather than interpreting them. Not referring back to original purpose/hypothesis.