Call durations are modelled by a Normal distribution with known standard deviation 2 minutes. The claimed population mean is 8 minutes. A random sample of 40 calls has mean 8.55 minutes.
Test at the 5% significance level whether the mean duration is greater than 8 minutes.
Explain how increasing the sample size, while keeping the same observed sample mean and assumed standard deviation, would affect the p-value.
328 exam-style questions on WJEC A Level Maths 4.2 Statistical distributions (A-level only), covering 4.2.1 Statistical distributions (A-level only), 4.2.2 Statistical distributions (A-level only), and 4.2.3 Statistical distributions (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.