For a sample of the past 30 monthly stock returns for McCreary, Inc., the mean return is 4% and the sample standard deviation is 20%. Since the population variance is unknown, the standard error of the sample is estimated to be: $S_X = \frac{20\%}{\sqrt{30}} = 3.65\%$. What is the 95% confidence interval for the mean monthly return? | Financial Risk Manager Part 1 Quiz - LeetQuiz