A psychologist compares two ways of presenting instructions in a categorisation task. The table shows how many participants correctly sorted all 12 cards.
| Group | Number of participants | Participants who correctly sorted all 12 cards |
|---|---|---|
| A | 24 | 7 |
| B | 36 | 9 |
Using the data for both groups, what fraction of the whole sample sorted every card correctly? Give the fraction in its simplest form and show each stage of your calculation.
173 exam-style questions on OCR GCSE Psychology 7.3 Analysing Research, covering 7.3.1 Types of Data, 7.3.2 Measures of central tendency, 7.3.3 Other descriptive statistics, 7.3.4 Tables, Charts and Graphs, 7.3.5 Reliability, 7.3.6 Validity and effects on validity, and 7.3.7 Sources of bias. Each one has a worked solution and a mark scheme showing where the marks go.