A sales analyst wants to determine whether there is a difference in the mean monthly sales of a company's four sales regions. Several salespersons from each region are randomly selected and each provides his or her sales amounts (in thousands of dollars) for the previous month. The results are listed in the following table. At alpha = 0.05, can the analyst conclude that there is a difference in the mean monthly sales among the sales regions? Assume that each population of sales is normally distributed and that the population variances are equal.