degrees of freedom

Question 1

what are degrees of freedom?

Answer 1

number of independent values associated with different calculations
combination of the amount of data (sample size) and the number of things being calculated

Question 2

residual degrees of freedom

Answer 2

n - k - 1
SSresidual calculation is based on the model, where we estimate k B term (-k) and intercept (-1)

Question 3

total degrees of freedom

Answer 3

n - 1
SStotal is based on the observed yi and ybar
to estimate ybar all apart from one value of y is free to vary, hence n - 1

Question 4

model degrees of freedom

Answer 4

SS model is dependent on estimated Beta, hence k (number of predictors)