Question

The tensile strength of a certain type of wire is normally distributed with a mean of 102.3 and a standard deviation of 4.6. find the standard error of the mean of a sample of 81 wires.

Answer 1

Standard error of the mean is defined as the standard deviation of the mean of the sampling distribution. The formula is expressed as the ratio of the standard deviation of the sample and the square root of the sample size.
SE = s / (√n)
SE = 4.6 / √81
SE = 0.51