Use this information to answer questions 15 - 20. A manufacturer of car tires de

Question

Use this information to answer questions 15 - 20. A manufacturer of car tires developed a new tread design that they hoped would extend tire life. To test the new design (Design 2) relative to the old design (Design 1) the company put a Design 1 and a Design 2 tire on the rear wheels of 20 consumers cars then compared the times until each of the tires wore out. That data and the Excel output of the statistical test are below. Design 1 Design 2 Mean 73.6 69.05 Variance 242.779 316.366 Observations 20 20 Pearson Correlation 0.915 Hypothesized Mean Difference 0 df 19 t Stat 2.818 P(T<=t) one-tail 0.005 t Critical one-tail 1.729 P(T<=t) two-tail 0.011 t Critical two-tail 2.093

This is a ____ test. Select one: a. Difference of proportions b. Two-factor ANOVA c. Difference of means for matched pairs d. Difference of independent sample means

Question 16 Not yet answered Marked out of 3.34 Not flaggedFlag question Question text The correct null hypothesis is Select one: a. The sample proportions are not the same b. The sample means are the same c. The sample means are not the same d. The sample proportions are the same

Question 17 Not yet answered Marked out of 3.34 Not flaggedFlag question Question text Using a 5% significance level, is there a difference in tire performance? Select one: a. Yes b. Cannot be determined c. No Question

18 Not yet answered Marked out of 3.34 Not flaggedFlag question Question text What is the correct conclusion from the test? Select one: a. Reject the null. The means are not the same b. Do not reject the null. The means are the same c. Accept the null hypothesis. The means are the same d. Accept the alternative hypothesis. The means are not the same

Question 19 Not yet answered Marked out of 3.34 Not flaggedFlag question Question text Should the company adopt the new tire design (Design 2)? Select one: a. Cannot be determined b. No c. Yes Question 20 Not yet answered Marked out of 3.34 Not flaggedFlag question Question text Which of the following is accomplished by using this design for the study instead of giving 20 drivers Design 1 tires and 20 drivers Design 2 tires? Select one: a. The compared tires experienced the same driving conditions b. All of these were accomplished with this study design c. The compared tires were tested during the same time period d. The compared tires experienced the same driving habits

Explanation / Answer

15) option D is right

This is a  Difference of independent sample means test

16) option B is right

The sample means are the same

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