The dashed-line distribution has 15 degrees of freedom. The solid-line distribution has 3 degrees of freedom.

Chi-square distributions with different degrees of freedom For example, the following figure depicts the differences between chi-square distributions with different degrees of freedom. Many families of distributions, like t, F, and chi-square, use degrees of freedom to specify which specific t, F, or chi-square distribution is appropriate for different sample sizes and different numbers of model parameters. (If you want to practice calculating chi-square probabilities then use df n. Adding parameters to your model (by increasing the number of terms in a regression equation, for example) 'spends' information from your data, and lowers the degrees of freedom available to estimate the variability of the parameter estimates.ĭegrees of freedom are also used to characterize a specific distribution. where df degrees of freedom which depends on how chi-square is being used. Where n1 is the sample size of group 1 and n2 is the sample size of group 2. Increasing your sample size provides more information about the population, and thus increases the degrees of freedom in your data. The table below gives formulas to calculate the degrees of freedom for several commonly used tests.

This value is determined by the number of observations in your sample and the number of parameters in your model. The degrees of freedom (DF) are the amount of information your data provide that you can 'spend' to estimate the values of unknown population parameters, and calculate the variability of these estimates.

Calculate degrees of freedom chi square