Question:

a) Assume that the two independents samples shown above for Mercedes and BMW have been collected from normal distributions. Check the assumption of common variance of the two populations (Equal Variances).

b) Manually find the 95% confidence interval for the difference of the two means (Mean age of Mercedes cars and the mean age of BMW cars).

c) A researcher is interested in comparing the ages of Mercedes and BMW cars sold for the first time by their owners.

Using the computed confidence interval in part b, test the claim that the mean age of Mercedes cars sold for the first time by their owners is different from that of BMW.

i. State your hypothesis in English

ii. State your justified decision.

iii. What does that mean? (state your conclusion)

Using the p-value method, test the claim that the mean age of Mercedes cars sold for the first time by their owners is different from that of BMW.

i. Carry out the test and find the p-value (USE MINITAB).

ii. State your decision

iii. What does that mean? (state your conclusion)