A researcher expects the amount of fertiliser used on a field to be associated with a change in crop yield, but does not know whether the association will be positive or negative.
State whether a one-tailed or two-tailed test should be used. Give a reason.
308 exam-style questions on WJEC A Level Maths 4.3 Statistical hypothesis testing (A-level only), covering 4.3.1 Statistical hypothesis testing (A-level only) and 4.3.2 Statistical hypothesis testing (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.