STEP 1: Compute the mean
The mean of the dataset is the sum of the elements divided by their number:
STEP 2: Compute the residuals
You have to compute the difference between every element and the mean:
Step 3: Square the residuals:
Step 4: Sum the squared the residuals:
Step 5: Divide by the number of elements in the dataset:
Step 6: Consider the square root of the result:
The formula we used is
where is the standard deviation,
are the elements in the dataset,
is the number of elements in the dataset, and
is the mean of the dataset.