Dr. Harrison decided to use the standard deviation as a measure of dispersion for his psychological data. Calculate the standard deviation for the stress recovery times shown in Table 2.
You must show your working and give your answer to two decimal places.
Table 2
| Participant | Stress recovery time xxx (minutes) | (x−xˉ)(x - \bar{x})(x−xˉ) | (x−xˉ)2(x - \bar{x})^2(x−xˉ)2 |
|---|---|---|---|
| P | 12 | -2.5 | 6.25 |
| Q | 18 | 3.5 | 12.25 |
| R | 15 | 0.5 | 0.25 |
| S | 9 | -5.5 | 30.25 |
| T | 21 | 6.5 | 42.25 |
| U | 14 | -0.5 | 0.25 |
| V | 10 | -4.5 | 20.25 |
| W | 17 | 2.5 | 6.25 |
| Total | 116 | Total | |
| Mean xˉ\bar{x}xˉ | 14.5 |
Practise Edexcel A Level Psychology Methods with exam-style questions for A Level Psychology. 100 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.