Suppose that you are testing the hypotheses Ho: u = 12 vs. HA: u > 12. A sample of size 25 results in a sample mean of 11.5 and a sample standard deviation of 2.0. a) What is the standard error of the mean? b) What is the critical value of t* for a 90% confidence interval? c) Construct a 90% confidence interval for u. d) Based on the confidence interval, at a = 0.05 can you reject Ho? Explain. . . . a) The standard error of the mean is (Type an integer or a decimal.) b) The critical value is t* = (Round to three decimal places as needed.) c) The 90% confidence interval for u is (Round to two decimal places as needed.) d) Since the hypothesized mean the values contained in the confidence interval, Ho (Type an integer or a decimal.)