The owner of a fish market has an assistant who has determined that the weights of catfish are normally distributed, with mean of 3.2 pounds and standard deviation of 0.8 pound. If a sample of 64 fish yields a mean of 3.4 pounds, what is probability of obtaining a sample mean this large or larger?
A) 0.0228
B) 0.0013
C) 0.0001
D) 0.4987

Question

Quizplus · Accepted Answer

The standard error of the mean is 0.1 (0.8/√64). The z-score for a sample mean of 3.4 is (3.4-3.2)/0.1 = 2. The probability of obtaining a z-score of 2 or higher is 0.0228.

The Owner of a Fish Market Has an Assistant Who