Testing: Ho: u 18.6 Your sample consists of 20 values, with a sample mean of 19.5. Suppose the population standard deviation is known to be 2.33. a) Calculate the value of the test statistic, rounded to 2 decimal places. Z b) At a = 0.02, the rejection region is O z > 2.33 Oz 2.05 Oz 2.33 Oz 2.05 c) The decision is to O Reject the null hypothesis Accept the alternative hypotheis O Accept the null hypothesis O Fail to reject the null hypothesis d) Suppose you mistakenly failed to reject the null hypothesis in this problem, what type of error is that? Type II O Type