Even if the null hypothesis is rejected, it does not mean that all of the variables in
the equation have regression coefficients that are significantly different from
zero. In order to test whether a particular coefficient is zero, we first look at the
column labeled t in Tables 10.8 and 10.9, which are derived from Tables 10.2
and 10.3 respectively. This column is computed by dividing each coefficient
by its standard error and using equation (10.3). The degrees of freedom are