Work out the standard deviation and variance (sample and population).
Separate numbers with a comma, space or new line.
Two datasets can share the same average yet feel completely different — one tightly clustered, the other all over the place. Standard deviation is the number that captures that spread.
It is the square root of the variance, which is the average of the squared differences from the mean. For the values 2, 4, 4, 4, 5, 5, 7, 9 the mean is 5 and the population standard deviation is 2, meaning values sit about 2 away from the mean on average.
The calculator gives both the sample and population versions along with the variance and mean — useful for lab results, quality control, finance and statistics coursework.
Use population when your numbers are the entire group, and sample (which divides by n−1) when they are a subset you are using to estimate a larger group. The calculator shows both.
That the values are widely spread from the mean. A small standard deviation means they cluster tightly around it. It is always in the same units as your data.
It means the values are clustered near the mean.