Calculate sample or population variance and standard deviation.
Data Input
Statistical Results
Sample Variance250Squared deviation
Mean (Average)30.00
Std. Deviation15.8114
Sum of Squares (SS)1000.00
Sample Size (n)5
About this calculator
Overview
Variance measures the average squared distance from the mean. It quantifies how spread out a dataset is. Using squared differences ensures all values are positive and penalizes larger outliers more heavily.
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Pro Tips
Use 'Sample' if you are working with a subset of a larger group.
Use 'Population' if you have data for every single member of the group.
Variance is sensitive to extreme values (outliers) because they are squared.
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Fun Facts
"Dividing by n-1 for samples is called Bessel's Correction. It corrects the bias in estimating population variance from a sample."
"Variance is measured in squared units (e.g., square meters). This is why we take the square root to get Standard Deviation, which is in the original units."
"A variance of zero means all values in the dataset are identical."
