Consider a hypothesis H, :u = 18 against Hi : + 18. The test is? Select one: a. Cross tailed b. Left tailed c. Right tailed d. Two tailed A sample of 50 students was taken from the local university. These students spent an average of $170 on books this semester, with a standard deviation of $25.50. A 95% confidence interval for the average spent on books for all students would be Select one: a. 164.05