The time needed for college students to complete a certain paper-and-pencil maze follows a normal distribution with a mean of 30 seconds and a standard deviation of 2.3 seconds. You wish to see if the mean time μ is changed by vigorous exercise, so you have a group of 20 college students exercise vigorously for 30 minutes and then complete the maze. It takes them an average of xˉ=30.4 seconds to complete the maze. Use this information to test the hypotheses H0​:μ=30 Ha​:μ=30 Conduct a test using a significance level of α=0.01 (a) The test statistic (b) The positive critical value, z⋆= (c) The final conclusion is A. There is not sufficient evidence to reject the null hypothesis that μ=30. B. We can reject the null hypothesis that μ=30 and accept that μ=30.