-2- 2. (Total 30 points) (a) (6 points) Obtain the value of z to be used to be used to determine 96% confidence interval with n= 20. (b) (6 points) Obtain the value of a suitable test statistic to be used to determine 99% confidence interval with n = 30 when sample variance is known but not population standard deviation. (c) (6 points) In a two sided test of hypothesis for mean, what is the critical value of a suitable test statistic that should be used when a sample of 25 has mean of 36.5 and variance of 2.9? Use 5% level of significance. Why is this test statistic chosen? (d) (6 points) In a one tailed (upper tail) test of hypothesis for mean, write the decision rule if the critical value of t is given to be 2.1315 with n= 16. (e) (6 points) In a one tailed test of hypothesis for mean, what level of significance is used if the decision rule is: Reject Hoif zs S-2.17? - 3