An environmental scientist wants to investigate whether the noise levels (measured in decibels, dB) in a local nature reserve differ before and after a nearby bypass road is opened. She measures the peak noise levels at 10 specific locations within the reserve on a weekday afternoon before the opening, and again on a weekday afternoon after the opening. The differences in noise levels cannot be assumed to be normally distributed.
Identify an appropriate statistical test that the scientist could use and justify your choice.
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.