An investigation was carried out to determine if there is an association between the shell type of hermit crabs and their choice of burrowing zone in a test arena containing microplastics.
A sample of 90 hermit crabs was classified by shell type as either 'Gastropod Shell' or 'Bivalve Shell'. Each crab was placed in a test arena containing three distinct zones: Zone A (microplastic-treated sand), Zone B (pristine sand), or Zone C (rocky substrate). The zone each crab chose to burrow in was recorded.
The researcher decided to use a Chi-Squared test of association to analyse the data. One reason for choosing this test was that the observations are independent (each crab only contributes to one count in the contingency table).
Referring to information about this study, explain two other reasons why it was appropriate to use a Chi-Squared test of association in this case.
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.