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 Reiser Shaw

1 43 37 41 43

2 46 38 45 45

3 43 39 42 46

Referring to the information above, what is the numerator degrees of freedom for Levene's test for homogeneity of variances?(The answer is a number; you can enter it as either a numeral or a word.)