An agricultural scientist is investigating the relationship between the concentration of a novel trace mineral, lithium-silicate, in soil (measured in parts per million) and the weekly growth rate of a rare alpine herb, Artemisia nivalis (measured in mm). The scientist wants to determine whether or not a relationship exists between these two variables.
To conduct the research, the scientist monitors twenty isolated test plots in a controlled greenhouse environment.
The scientist decides to use a two-tailed hypothesis test to analyze the correlation.
Explain why a two-tailed test, rather than a one-tailed test, is appropriate for this investigation.
121 exam-style questions on AQA A Level Psychology Inferential testing (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.