Find the mean of the data set
Subtract the mean from each data value
Square each result
Add all the squared results
Divide by the number of data values for population standard deviation
Divide by one less than the number of data values for sample standard deviation
Take the square root of the result
Population formula: σ = √[Σ(x – μ)² / N]
Sample formula: s = √[Σ(x – xÌ„)² / (n – 1)]