A yogurt company claims that it prints a free yogurt coupon under a randomly selected 20% of its lids. A loyal customer purchases 85 yogurt cups, and records whether each was a winner. After consuming all 85 cups, he is disappointed to see that only 12 (14.1%) of his yogurt cups contained coupon codes. He performs a 99% confidence interval for the proportion of yogurt cups containing coupon codes, obtaining (0.044, 0.238). What conclusion can the customer draw about the yogurt company’s claim?
Answer
A
The company’s claim may be justified because 0.2 is in the confidence interval.
B
The company’s claim is definitely justified because 0.2 is in the confidence interval.
C
The company’s claim is not justified because the upper endpoint of the confidence interval is 0.238.
D
The company’s claim is not justified because 12 out of 85 (0.141) is far less than 0.2.