Question
Seventy million pounds of trout are grown in the U.S. every year. Farm-raised trout contain an average of 32 grams of fat per pound, with a standard deviation of 8 grams of fat per pound. A random sample of 40 farm-raised trout is selected. The mean fat content for the sample is 30.7 grams per pound. Find the probability of observing a sample mean of 30.7 grams of fat per pound or less in a random sample of 40 farm-raised trout. Carry your intermediate computations to at least four decimal places. Round your answer to at least three decimal places.
Explanation / Answer
Solution:
Compute
Z=(30.7-32)/[8/sqrt(40)]
= -1.03
You should use the t-distribution with 40-1=39
deg. freedom since 39 is a moderately small sample.
From the z- table, the area to the left of P (z<-1.03) is 1 - 0.8485 = 0.1515
Answer: 0.1515