Question: Comfy wonders whether the customers who receive larger discounts are buying more expensive items. Recalling that the value in the Tot Paid column is after the discount, find a 95% confidence interval for the difference between the mean original price per item for customers who purchase something with the 5% coupon and the similar mean for customers who purchase something with the 10% coupon. Repeat with 5% and 10% replaced by 10% and 15%. What can you conclude?