A random sample of 200 purchases at an online bookstore showed that the average purchase is $43.26 with the standard deviation of $20.67. The analyst wants to know if the mean purchase of all transaction is greater than $40.

(a) What is the null hypothesis and the alternative hypothesis? Is it a one-sided or two-sided hypothesis test?

(b) What is the value of the test statistic?

(c) What is the p-value? [Tips: you can use an online calculator to compute (x) of a standard normal distribution https://stattrek.com/online-calculator/normal.aspx]

(d) Suppose = 0.05, so Z0.05 = 1.64 and Z0.025 = 1.96. Can you reject the null hypothesis?