Copeman is a private medical clinic. It has a total of 185 locations in B.C. and Ontario. In their efforts to rebrand the company to make it look more luxurious, all the locations were renovated last year. The executives randomly sampled 25 locations from each province and compared their respective sales revenues before and after renovations. Results:
Sample mean of the differences, $5,285
Sample standard deviation of the differences, $25,875