Final answer:
The probability of observing a sample mean of 31.5 grams of fat per pound or less in a random sample of 40 farm-raised trout is 0.473.
Step-by-step explanation:
To find the probability of observing a sample mean of 31.5 grams of fat per pound or less in a random sample of 40 farm-raised trout, we can use the Z-score formula and the standard normal distribution.
First, calculate the Z-score: Z = (sample mean - population mean) / (standard deviation / sqrt(sample size))
Z = (31.5 - 32) / (7 / sqrt(40)) = -0.0717
Next, look up the Z-score in the standard normal distribution table to find the corresponding probability. In this case, the probability is 0.4726.
Rounding the answer to three decimal places, the probability of observing a sample mean of 31.5 grams of fat per pound or less in a random sample of 40 farm-raised trout is 0.473.