Question

13. Do cars with more cylinders weigh more? A student who wishes to answer this question uses a random selection procedure to collect data on fourteen cars in his hometown. He categorizes the cars by the number of cylinders they have (four, six, or eight) and t of the car by means of the recorded weight in the owner's manual. The data are given below. Number of cylinders 6 2464 2472 3169 2489 2587 3205 2560 3060 3940 3190 3193 3945 3210 3525 4 The data are to be analyzed with the Kruskal-Wallis test. At the 5% significance level, would we reject the null hypothesis?

Answer 1

Null Hypothesis: Ho: Cars with more cylinders weigh same. Alternative Hypothesis H Cars with more cylinders weigh more. Rejection rule: If p-value α (-0.05 ) , then reject the null hypothesis Ho EXCEL Mega Stat in Add-Ins) procedure: Step 2: In Input range, enter the values as Al:C7 Step 3: Check the Correct for ties. Step 4: Click OK.

EXCEL Mega Stat in Add-Ins) output Kruskal-Wallis Test Median nAvg. Rank 2,524.50 4 3,126.50 6 3.572.50 4 4.00 4 cylinders 7.50 6 cylinders 11.00 8 cylinders Total 3.179.50 14 5.600 H 2 d.f 0608 p-value multiple comparison values for avg. ranks 6.56 (.05) 8.04 01) Thus the value of test statistic is 5.6 and the p-value is 0.0608 Conclusion Use a significance level, α 0.05 Here, p-value is 0.0608, which is greater than the value of α 0.05. That is, p-value(-0.0608) >α(-0.05) Therefore, by the rejection rule, do not reject the null hypothesis H

Interpretation There is insufficient evidence at level of significance α Cars with more cylinders weigh same. 0.05-