Df

Degrees of freedom in terms of n and p, where n= sample size, and p= number of x variables:

1. Df numerator (Df₁) = p
2. Df denominator (Df₂) = n-p-1
3. Df total (Df_T) =  (n-1)
4. Sample size (also shown as n) = Df total + 1

Df are also reported in the ANOVA table output. The df reported next to Regression (equivalent to SSTR from chapter 13 i.e. Anova) are called Df1 (or df numerator). The df reported next to Residual (equivalent to SSE from chapter 13 i.e. Anova) are called Df2 (or df denominator). The df reported next to Total (or SST from ch13 Anova) are also called Df total.

 

 

In the example above df1 = 2, df2 = 5 and df total = 7.

The sample size which I had in my data view of the SPSS file was 8. Hence the df total is 7 because df total is always equal to sample size – 1.