As part of an evaluation program, a sporting goods retailer wanted to compare the downhill coasting speeds of four brands of bicycles. She recorded three trials of each brand and determined their maximum downhill speeds. The results are presented in kilometres per hour in the table below. Trial Barth Tornado Raiser Shaw I 43 37 41 43 2 46 38 45 45 3 43 3'3 42 46 Referring to the information above, the value of the mean square within MSWis . Answer to 2 d.p