Question

Suppose a study reports that the average price for a gallon of self-serve regular unleaded gasoline is $3.76. You believe that the figure is higher in your area of the country. You decide to test this claim for your part of the United States by randomly calling gasoline stations. Your random survey of 25 stations produces the following prices.

$3.87	$3.89	$3.76	$3.80	$3.97
3.80	3.83	3.79	3.80	3.84
3.76	3.67	3.87	3.69	3.95
3.75	3.83	3.74	3.65	3.95
3.81	3.74	3.74	3.67	3.70

Appendix A Statistical Tables

Assume gasoline prices for a region are normally distributed. Do the data you obtained provide enough evidence to reject the claim? Use a 1% level of significance. (Round the intermediate values to 2 decimal places. Round your answer to 2 decimal places.)

The value of the test statistic is t =    and we                                                           reject the null hypothesisfail to reject the null hypothesis.

Answer 1

Answer: Suppose a study reports that the average price for a gallon of self-serve regular unleaded gasoline is $3.76. You believe that the figure is higher in your area of the country. You decide to test this claim for your part of the United States by randomly calling gasoline stations. Your random survey of 25 stations produces the following prices.

Solution:

The hypothesis test:

Null hypothesis, Ho: μ ≤ 3.76

Alternative hypothesis, Ha: μ > 3.76