The height of sunflower seedlings in a nursery is normally distributed with a mean of 15.5 cm and a standard deviation of 1.2 cm.
Find the probability that a randomly selected seedling has a height of less than 13.0 cm.
Write down the null and alternative hypotheses to test if the mean seedling height is lower than 15.5 cm.
A sample of 25 seedlings is measured and the mean height is found to be 15.0 cm. Carry out a test at the 2.5% significance level to see if there is evidence that the mean height of the seedlings is less than 15.5 cm.
355 exam-style questions on OCR (MEI) A Level Maths 2.5 Statistical Hypothesis Testing, covering 2.5.1 Process and language of hypothesis testing, 2.5.2 When to apply 1-tail and 2-tail tests, 2.5.3 Significance level and incorrect rejection, 2.5.4 Null and alternative hypotheses (binomial), 2.5.5 Conduct a binomial hypothesis test, 2.5.6 Critical and acceptance regions (binomial), 2.5.7 Distribution of the sample mean (A-level only), 2.5.8 Hypothesis test for a single mean (A-level only), 2.5.9 Critical and acceptance regions (mean) (A-level only), 2.5.10 Correlation as closeness to a straight line (A-level only), 2.5.11 Inference using a correlation coefficient (A-level only), and 2.5 Statistical Hypothesis Testing. Each one has a worked solution and a mark scheme showing where the marks go.