Questions 20 and 21 are related to the following In a hypothesis test the objective is to test if the population mean is greater than 620. The P-value for the test, using the standard normal (z) distribution, is reported to be 0.0392. 20 What is the value of the test statistic? a 1.70 b 1.76 1.82 1.89 21 In the previous hypothesis test the sample standard deviation is 125. The sample size is 750. What is the sample mean? a 628.03 b 631.19 C 634.36 637.55