For a sample of the past 30 monthly stock returns for McCreaery, Inc., the mean return is 4% and the sample standard deviation is 20%. The population variance is unknown but the standard error of the sample mean is estimated to be: $S_{\bar{x}} = \frac{20\%}{\sqrt{30}} = 3.651\%$. What is the 95% confidence interval for the mean monthly return? | Financial Risk Manager Part 1 Quiz - LeetQuiz