Using the data in Table 2, calculate the standard deviation for the number of words recalled by the participants under high-stress conditions.
You must show your working and give your answer to two decimal places.
Table 2: Memory test scores under high-stress conditions and standard deviation calculations
| Participant | Number of words recalled (out of 15) | (x−xˉ)(x - \bar{x})(x−xˉ) | (x−xˉ)2(x - \bar{x})^2(x−xˉ)2 |
|---|---|---|---|
| A | 5 | -3 | 9 |
| B | 11 | 3 | 9 |
| C | 9 | 1 | 1 |
| D | 6 | -2 | 4 |
| E | 12 | 4 | 16 |
| F | 8 | 0 | 0 |
| G | 7 | -1 | 1 |
| H | 10 | 2 | 4 |
| I | 5 | -3 | 9 |
| J | 7 | -1 | 1 |
| Total | 80 | Total | |
| Mean (xˉ\bar{x}xˉ) | 8 |
Practise Edexcel A Level Psychology Methods with exam-style questions for A Level Psychology. 638 questions, matched to the Edexcel A Level Psychology (9PS0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.