The marketing department for an upscale retail catalog company wants to determine if there are differences in the mean customer purchase amounts across the available purchase sources (Internet, phone, or mail-in). Accordingly, samples were taken for 20 random orders for each purchase source. The ANOVA table produced shows that SSB (sum of squares between groups) = 12715.23 and SST (sum of squares total) = 849419.93. Based on this information, what would be the value of the test statistic used to test whether the mean purchase amount is different across the three purchase sources? Assume purchase amounts are normally distributed. Round your final answer to two decimal places. .