They use the variances of the samples to assess whether the populations they come from differ from each other.
Statistical tests like variance tests or the analysis of variance (ANOVA) use sample variance to assess group differences. Using variance to assess group differences If you have uneven variances across samples, non-parametric tests are more appropriate. Uneven variances between samples result in biased and skewed test results. These tests require equal or similar variances, also called homogeneity of variance or homoscedasticity, when comparing different samples. Variance is important to consider before performing parametric tests. Homogeneity of variance in statistical tests
Standard deviation is expressed in the same units as the original values (e.g., meters).It’s the square root of variance.īoth measures reflect variability in a distribution, but their units differ:
The standard deviation is derived from variance and tells you, on average, how far each value lies from the mean. Steps for calculating the variance by hand.