How to Calculate Standard Deviation: Population vs Sample Methods Explained
Learn the two methods to calculate standard deviation—population and sample—and how to apply each formula correctly.
140 views
The two ways to calculate standard deviation are the population standard deviation and the sample standard deviation. Population standard deviation is used when you have the entire dataset (divide by N). Sample standard deviation is used when you have a sample of the population (divide by N-1). To calculate: find the mean, subtract the mean from each number, square the results, find the mean of these squares, and take the square root.
FAQs & Answers
- What is the difference between population and sample standard deviation? Population standard deviation uses the entire dataset and divides by N, while sample standard deviation uses a subset of data and divides by N-1 to correct bias.
- How do you calculate standard deviation step-by-step? First, find the mean of the data, subtract the mean from each number, square the results, find the average of these squared differences, and then take the square root.
- When should I use sample standard deviation instead of population standard deviation? Use sample standard deviation when you only have a sample or part of the data rather than the entire population.