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 |
638 exam-style questions on Edexcel A Level Psychology Methods. Each one has a worked solution and a mark scheme showing where the marks go.