A researcher investigates the yield of two varieties of wheat, Variety X and Variety Y. They believe that Variety X has a higher mean yield than Variety Y. A random sample of 60 plots of Variety X produced a mean yield of 445 kg with a standard deviation, sXs_XsX, of 32 kg. Another random sample of 75 plots of Variety Y produced a mean yield of 432 kg with a standard deviation, sYs_YsY, of 24 kg.
Stating your hypotheses clearly and using a 5% level of significance, test whether or not the researcher's belief is supported by the data.
130 exam-style questions on WJEC A Level Maths 4.3.2 Statistical hypothesis testing (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.