An agricultural research team investigated the effects of two organic soil conditioners on the growth of legacy tomato plants. They measured the height of the plants in two separate greenhouses before applying the conditioners, and then measured them again after an eight-week cultivation period.
Group Alpha received Soil Conditioner A (standard vermicompost).
Group Beta received Soil Conditioner B (seaweed-infused vermicompost).
Plant heights were measured in centimetres. The shortest plant recorded at the start was 12.4 cm and the tallest was 32.8 cm.
Table 1: Mean plant height (cm) for Group Alpha (Soil Conditioner A) and Group Beta (Soil Conditioner B) after eight weeks
| Group Alpha (Soil Conditioner A) | Group Beta (Soil Conditioner B) | |
|---|---|---|
| Mean plant height (cm) | 78.5 | 96.2 |
Explain why the data in Table 1 does not enable the researchers to draw valid conclusions about the relative effectiveness of the two soil conditioners. State what the researchers should do to address this issue.
Practise AQA A Level Psychology Scientific processes with exam-style questions for A Level Psychology. 689 questions, matched to the AQA A Level Psychology (7182) 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.
