An agricultural scientist conducted an experiment to investigate whether a new organic fertilizer formulation (Variety A) produces a more consistent yield of tomatoes compared to the standard organic fertilizer (Variety B). A sample of 12 experimental plots was divided equally, with 6 plots assigned to Variety A and 6 plots to Variety B. The total tomato yield (in kg) for each plot at the end of the harvest is shown below:
| Variety A | Variety B | ||
|---|---|---|---|
| Plot | Yield (kg) | Plot | Yield (kg) |
| 1 | 14.2 | 1 | 12.1 |
| 2 | 15.8 | 2 | 17.4 |
| 3 | 13.5 | 3 | 11.0 |
| 4 | 16.1 | 4 | 16.5 |
| 5 | 14.9 | 5 | 13.8 |
| 6 | 15.5 | 6 | 15.2 |
Explain how you would calculate the standard deviation for the yield of each variety of tomato plant in this study.
513 exam-style questions on OCR A Level Psychology Data recording, analysis and presentation. Each one has a worked solution and a mark scheme showing where the marks go.