The daily rainfall in a certain region during the monsoon season is modeled by a normal distribution with a mean of 22 mm and a standard deviation of 6.8 mm. A researcher believes that recent climate shifts have caused the mean daily rainfall to increase. A random sample of 40 days during the current monsoon season is taken, and the mean daily rainfall is found to be 24.5 mm. Carry out a hypothesis test at the 5% significance level to investigate the researcher's claim.
132 exam-style questions on OCR (MEI) A Level Maths 2.5.8 Hypothesis test for a single mean (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.