Scientists investigated the effect of a maternal gene variant, PLAC8-T\textit{PLAC8-T}PLAC8-T, on the birth mass of lambs. They classified the birth mass of 1200 lambs into two categories: 'standard' (3.5–4.5 kg3.5\text{--}4.5\text{ kg}3.5–4.5 kg) and 'extreme' (less than 3.5 kg3.5\text{ kg}3.5 kg or greater than 4.5 kg4.5\text{ kg}4.5 kg), and cross-referenced this with the presence or absence of the PLAC8-T\textit{PLAC8-T}PLAC8-T allele in the mother's genome. They wished to test the following null hypothesis: 'The presence of the PLAC8-T\textit{PLAC8-T}PLAC8-T allele in the maternal genome has no effect on the frequency of lambs born with extreme birth mass.'
State the name of the statistical test that the scientists should use with this categorical frequency data.
The statistical test yielded a PPP-value of 0.0240.0240.024. Explain what the scientists can conclude from this result about their null hypothesis.
21 exam-style questions on AQA A Level Biology Investigating diversity. Each one has a worked solution and a mark scheme showing where the marks go.