Question

George, a marketing analyst at a tech company, believes tablet sales are decreasing at the company. He would like to test the claim that the average number of tablet sales per month is under 150 sales. Using the computed test statistic of −1.56 and the critical value of −1.96, is there enough evidence for the marketing analyst to reject the null hypothesis? Use the graph below to interpret the critical value. First select the appropriate test type (left-, right-, or two- tailed), then plot the points along the x-axis (for the critical value and test statistic), and use them to choose the appropriate interpretation.

Answer 1

The test statistic of -1.56 is not less than the critical value of -1.96; hence, there is not enough evidence to reject the null hypothesis in this one-tailed test.

Step-by-step explanation:

George, the marketing analyst, is testing the claim that the average number of tablet sales per month is under 150, which is a one-tailed test to the left. Since the computed test statistic is -1.56 and the critical value is -1.96, we place these points on a graph representing a normal distribution curve.

The test statistic does not fall to the left of the critical value (it is, in fact, greater than -1.96), which suggests that there is not enough evidence to reject the null hypothesis. In the context of hypothesis testing, if the test statistic were less than the critical value, it would have indicated that the null hypothesis could be rejected.

However, George's test statistic of -1.56 does not meet this criterion, so the conclusion is that there's no sufficient evidence to support the claim that tablet sales are less than 150 per month.