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Most individuals are aware of the fact that the average annual repair cost for an automobile depends on the age of the automobile. A researcher

Most individuals are aware of the fact that the average annual repair cost for an automobile depends on the age of the automobile. A researcher is interested in finding out whether the variance of the annual repair costs also increases with the age of the automobile. A sample of 26 automobiles 4 years old showed a sample standard deviation for annual repair costs of $171.18 and a sample of 23 automobiles 2 years old showed a sample standard deviation for annual repair costs of $118.75. Let 4 year old automobiles be represented by population 1. The data is located in the Microsoft Excel Online file below.

Car Age and Repair Cost ($) F-Test Two-Sample for Variances
4 years 2 years
788 637 4 years 2 years
839 431 Mean 784.6154 450.7826
778 454 Variance 29301.93 14101.54
791 404 Observations 26 23
889 410 df 25 22
791 713 F 2.077924
775 573 P(F<=f) one-tail 0.043639
943 469 F Critical one-tail 2.019644
1013 155
943 419
1060 399 Significance Level (alpha) 0.05
405 524
955 396 Test Statistic (2 decimals) 2.08
874 548
886 396 Critical Value (2 decimals) 2.02
336 598
733 391 p-value (4 decimals) 0.0436
654 336
507 370 Reject the null hypothesis? Yes
823 455
708 356
808 365
898 569
790
801
612

State the null and alternative versions of the research hypothesis that the variance in annual repair costs is larger for the older automobiles.

H 0 : 21

H a : 21

2. Conduct the hypothesis test at a 0.01 level of significance.

Calculate the value of the test statistic (2 decimals).

2.08

Calculate the critical value (2 decimals).

2.02 <------- This is flagging as incorrect even inputting the formula given.

Calculate the p-value (4 decimals).

0.0436

Reject null hypothesis? No

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