From a population with a known standard deviation of 15, a sample of 25 observations is taken. Calculate the standard error of the sample mean. A. 3.00. B. 0.60. C. 1.67.
The standard error of the sample mean equals the standard deviation of the population divided by the square root of the sample size: sx = s / n1/2 = 15 / 251/2 = 3.
