The proportion of visitors to a webpage who click on a link is 0.15. Angela believes that increasing the font size of the link will increase this proportion.
After the font size is increased, a random sample of 90 visitors is taken, and 20 of them click on the link.
Stating your hypotheses clearly, test Angela's belief at the 5% significance level.
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.