An industrial psychologist wishes to study the effect of motivation on sales in a particular firm. 24 new salespersons are randomly divided into two groups of 12. One group is paid an hourly rate and the other group is only paid a commission. The sales volume (in thousands of dollars) is recorded for all 24 salespersons during the first month with the firm. The sample mean and standard deviation for the group paid hourly are 227.6 and 13.84, respectively. The sample mean and standard deviation for the commission group are 247.9 and 21.59, respectively. The psychologist is interested in finding evidence at the .05 significance level to support the notion that the incentive posed by offering a commission yields greater average sales volume.
Which of the following correctly describes the p-value for the test statistic in #6?
What critical value(s) would be used for comparison with the test statistic in #6?
What is the decision for the test statistic in #6?
Which of the following correctly describes the 90% confidence interval for the mean of the commission group minus the mean of the hourly group?