a)[2 marks]A 95% confidence interval for a difference in means is found to be (2.2, 4.5). If you did a test of the null hypothesis that there is no difference in means would you expect to get a p-value greater or less than 0.05? Give a reason.

b)[2 marks]If you construct both a 95% confidence interval and a 99% confidence interval for the same data, which would you expect to be wider? Give a reason.

c)[1 mark]Why is it uncommon for people to make 50% confidence intervals?