B1. (a) The weights in ounces of ten apples selected at random from a tree are given below. 4.3 5.8 5.9 6.0 6.3 3.5 3.4 6.6 5.1 6.1 Derive a 95% confidence interval for the mean weight of an apple. (b) What do you understand by the phrase "95% confidence interval"? (c) Assuming that the population variance is = 1, test at the 5% level of significance the null hypothesis that = 5 against the alternative hypothesis that 5. What do you conclude from your test? (d) What do you understand by the phrase "5% level of significance"?