Question

K.Brew sells a wide variety of outdoor equipment and clothing. The company sells both through mail order and via the internet. Random samples of sales receipts were studied for mail-order sales and internet sales, with the total purchase being recorded for each sale. A random sample of 9 sales receipts for mail-order sales results in a mean sale amount of $87.60 with a standard deviation of $27.75. A random sample of 16 sales receipts for internet sales results in a mean sale amount of $97.30 with a standard deviation of $23.75. Using this data, find the 95% confidence interval for the true mean difference between the mean amount of mail-order purchases and the mean amount of internet purchases. Assume that the population variances are not equal and that the two populations are normally distributed.

Step 1 of 3: Find the point estimate that should be used in constructing the confidence interval.

Step 2 of 3: Find the margin of error to be used in constructing the confidence interval. Round your answer to six decimal places.

Step 3 of 3: Construct the 95% confidence interval. Round your answers to two decimal places.

Answer 1

Point Estimate =  

Margin of Error =

Confidence interval :-



DF = 14


Lower Limit =
Lower Limit = -33.2747
Upper Limit =
Upper Limit = 13.8747
95% Confidence interval is ( -33.27 , 13.87 )