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.
316 exam-style questions on OCR A Level Maths 2.5 Statistical Hypothesis Testing, covering 2.5.1 The language of hypothesis testing, 2.5.2 Hypothesis test for a binomial proportion, 2.5.3 Inference and significance level, 2.5.4 Sample mean as a random variable (A-level only), 2.5.5 Hypothesis test for the mean of a normal distribution (A-level only), 2.5.6 Pearson's product-moment correlation coefficient, and 2.5.7 Hypothesis test using Pearson's coefficient (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.