Question

The average gasoline price at Chevron was $3.12 per gallon last month. Due to the recent nation-wide gas price drop, the chief marketing officer of Chevron believes that there has been a significant reduction in the average gas price. In order to test his belief, he randomly selected a sample of 36 of Chevron gas stations and found the average gas price of these stations was $3.06. Assume that the population standard deviation of the population is $0.12, and the significance level (α) is 5%.

A. Find the test statistic. Is this a z-score or a t-score?

Group of answer choices

z-score = -0.5 because population std is given to be $0.12

t-score = 3 because population std is not given, and the sample std is given to be $0.12

t-score = -0.5 because population std is not given, and the sample std is given to be $0.12

t-score = - 3 because population std is not given, and the sample std is given to be $0.12

z-score = - 3 because population std is given to be $0.12

z-score = 3 because population std is given to be $0.12

B. Critical Value Approach

Step 3: Using the critical value approach, what is the critical value?

Group of answer choices

1.960

-1.645

-1.960

1.688

1.690

1.645

-1.688

-1.690

Answer 1