Calculate degree of freedom for the outcome of lm.fit(). This function is built for reg.linreg for higher efficiency only.
It can't be used for calculating degree of freedom in general operation.
# NOT RUN {X <- as.matrix(cbind(1,EuStockMarkets[,1:2])) # create the design matrixY <- as.data.frame(EuStockMarkets)$FTSE
fit <- lm.fit(x = X, y = Y)
reg.dof(fit)
# }