Question: how to find the standard deviation of x bar?
Answer: Step 1: Calculate the mean of the data—this is xˉx, with, \bar, on top in the formula. Step 2: Subtract the mean from each data point. ...  Step 3: Square each deviation to make it positive. Step 4: Add the squared deviations together. Step 5: Divide the sum by one less than the number of data points in the sample.