a. Calculate the test statistic when x̄ = 145, s = 50, and n = 100. Use a 5% significance level. H0: µ = 150 H1: µ < 150 b. Repeat part (a) with x̄ = 140. c. Repeat part (a) with x̄ = 135. d. What happens to the t-statistic when the sample mean decreases?