ABSTRACT
Statistical Guide: See Exercises 20 and 21 to review the standard error of the mean. In those exercises, you computed 68% and 95% confidence intervals. It is also common to compute 99% confidence intervals. This means that we can have 99% confidence that the true mean (without sampling error) lies within this interval. To compute a 99% confidence interval, first multiply the standard error of the mean by 2.58.2 Then add the product to the mean to obtain the upper limit of the interval, and subtract it from the mean to obtain the lower limit of the interval.
