Next chapter: Confidence intervals

The number of degrees of freedom an estimate is based upon is equal to the number of independent scores that went into the estimate minus the number of parameters estimated en route to the estimation of the parameter of interest. In this case, there are N independent scores and one parameter (μ) is estimated en route to the estimation of the parameter of interest, σ² . Therefore the estimate has N-1 degrees of freedom. The formula for s² can then be written as:

where df = N-1. Naturally, the greater the degrees of freedom the closer the estimate is likely to be to σ².

Next chapter: Confidence intervals