Answer:
Estimate of the standard error of the mean = 0.38 lb
Explanation:
We are given the following in the question:
Sample mean,
= 10.87 lb
Sample size, n = 131
Standard deviation, σ = 4.31 lb
We have ti find the estimate of the standard error of the mean.
Formula for standard error:

Putting values, we get,

0.38 lb is the standard error of the mean.