The chance of a webpage visitor clicking on a link is 0.15. Angela believes that increasing the font size for the link will increase the proportion of visitors that click on the link.
After increasing the font size a sample of 90 visitors is taken and 20 clicked on the link.
Stating your hypotheses clearly test, at the 5% level of significance, whether or not there is evidence to support Angela's belief.
32 exam-style questions on WJEC A Level Maths 2.5.1 Statistical hypothesis testing. Each one has a worked solution and a mark scheme showing where the marks go.