Enter the mean calculated from your sample. It is the center value used to place the two limits.

Enter the sample's standard deviation, a measure of how spread out its values are. The calculation uses it to set the distance from the mean to each limit.

Enter the number of observations in your sample. The calculation uses this value to determine degrees of freedom and scale the sample spread.

Enter the desired confidence level as a percentage. The calculation uses it to choose the t percentile for the interval.