An agricultural scientist wants to investigate whether there is a linear correlation between the concentration of a particular soil nutrient, NNN (measured in parts per million, ppm), and the dry crop yield, YYY (measured in grams per square metre, g m−2\text{g m}^{-2}g m−2). The scientist collects data from 22 experimental plots.
The scientist decides to use a hypothesis test for the product-moment correlation coefficient (rrr) because they are looking for a linear association between two variables.
Explain one other condition about the data or the variables that must be satisfied for this test to be valid, referring specifically to the variables in this study.
Practise AQA A Level Psychology Inferential testing (A-level only) with exam-style questions for A Level Psychology. 123 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.
