2. The controlled assessment is worth 25% of the GCSE The project has three stages; 1. Planning 2. Collecting, processing and representing data 3. Interpreting and evaluating data

3.  Formulate a hypothesis  Plan a strategy for testing you’re your hypothesis Your hypothesis should be chosen so that you can use a variety of statistical techniques. You can have more than one related hypotheses. The hypotheses you chooses and strategies for testing them will help you to decide what data you need to collect. 10 marks Your investigation needs to involve comparison to obtain more than 4 marks

4.  Plan data collection Is your data primary or secondary, discrete or continuous? You should collect at least 25 pieces of data for each variable. You can use more if you wish but should consider the practicality of handling large amounts of data. (E.g. 30 males and 30 females). Choose and explain a suitable sampling method. If you choose to use a census (all the data) then explain why. Data can be collected using tally charts, grouped frequency tables or data loggers. (Include a sketch) 10 marks Required for 6 marks

5.  Plan diagrams Give reasons for your choice. E.g. use a scatter diagram to look for a relationship between two variables or a histogram to look at the shape of a distribution. You should always choose the most appropriate diagram for each hypothesis. There is no need to draw several diagrams to represent the same data. 10 marks If you do not give reasons for and of your decisions you can not obtain more than 2 marks You should include mid demand techniques to obtain more than 5 marks and at least one high demand technique for more than 7.

6.  Plan calculations  Anything else You must consider outliers. You should not do any calculations that do not answer your initial questions 10 marks Predict your results Identify any possible problems and ways of tackling them Required for 7 marks Required for 8 marks

7. DiagramsCalculation Low Demand Pictogram, Simple bar chart, Line graph, Data table, Simple pie chart, Two-way table (4 cells) Total Average Range Simple probability Mid Demand Two-way tables (more than 6 cells) Frequency polygons, Scatter diagrams Box plots, Cumulative Frequency Histograms (equal intervals) Formal identification of outliers Quartiles IQR High Demand Histogram (Unequal intervals) Comparative pie charts Normal distribution curves Spearman’s rank, Frequency density Standard deviation, Complex probability, Standardised scores

8.  Collect data At least 2 sets of data, each containing at least 25 pieces of information You should explain and justify the sampling method used and sample size (or reasons for using a census). Explain in detail how the data was collected. State its source whether it is primary secondary. Discuss the affect of leaving in or omitting any outliers. Required for 4 marks 8 marks Required for 5 marks Formally identifying whether there are any outliers is required for 7 marks

9.  To obtain full marks Discuss whether the sample collected is a good representation of the population. Discuss the reliability of the data. Discuss the problems that arose in collecting the data and what was done to solve the problems. All aspects of their data collection are justified.. 8 marks

10.  Complete calculations  Draw diagrams 12 marks You should include at least one calculation and one diagram. You should use the calculations/diagrams to make comparisons At least one mid demand technique should be used for 7 marks and more than one for 8. Required for 4 marks Required for 5/6 marks

11.  To obtain full marks 12 marks Comparative diagrams must have the same scale and be close to each other. All diagrams should be justified in your plan. Outliers are formally calculated. All data is interpreted in the conclusion. Your work is presented logically and is easy to follow High demand techniques are used

12.  Analyse and interpret your diagrams and calculations  Draw conclusions  Evaluate and suggest improvements 10 marks