J.J.Bean 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 18 18 sales receipts for mail-order sales results in a mean sale amount of $89.90 $ 89.90 with a standard deviation of $19.75 $ 19.75 .