Question 9:Suppose the alternative hypothesis in a hypothesis test is "the population mean is greater than 65". If the sample size is 50 and alpha = .05, the critical value of z is ______.a. 1.645b. -1.645c. 1.96d. -1.96Solution:This is a right-tailed test. For = 0.05, the critical z-value is 1.645.Answer: a. 1.645---Question 10:Suppose you are testing the null hypothesis that a population mean is less than or equal to 80, against the alternative hypothesis that the population mean is greater than 80. If the sample size is 49 and alpha = .05, the critical value of z is ______.a. 1.645b. -1.645c. 1.96d. -1.96Solution:This is a right-tailed test. For = 0.05, the critical z-value is 1.645.Answer: a. 1.645Solve them in details