Based upon extensive data from a national high school educational testing program, the standard deviation of national test score
s for critical reading was found to be 115 points. If a sample of 500 students are given the test, what would be the standard error of the mean? (rounded to the nearest 100th)
sd = 115 points, n = 500, degree of freedom = n-1 = 500-1 = 499, assuming a 95% confidence level, t-value corresponding to 499 degrees of freedom and 95% confidence level is 1.96501
Standard error of mean = 1.96501×115/√500 = 10.11 points (to the nearest 100th)
