6. To study the performance of a newly designed Mercedes, it was timed over a marked course under various wind and road conditions, and the following data (in minutes) was obtained: Calm conditions: 25, 18, 15, 21 Moderate conditions: 24, 27, 24, 19, 17, 22 Choppy conditions: 22, 24, 27, 25, 30 Perform an analysis of variance to test at the 0.05 level of significance whether the differences among the three-sample means are significant

7. The following data shows the average numbers of hours that six students studied per week and their grade point indexes: Hours studies 15 28 13 20 4 10 Grade point index 2.0 2.7 1.3 1.9 40.9 1.7 ? Test the null hypothesis ? = 0.1 against the alternative hypothesis ?

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