The t-tests of the partial regression coefficients : = 0 would seem to
suggest that four of the five independent variables are unimportant and could be
dropped from the model. the dependence of the partial regression coefficients and
sums of squares on the other variables in the model however, means that one must
be cautious in removing more than one variable at a time from the regression
model Removing one variable form the model will cause the regression coefficients
and the partial sums of squares for the remaining variables to change (unless they
are orthogonal to the variable dropped).