An attempt was made to construct a regression model explaining student scores in intermediate economics courses (Waldauer, Duggal, and Williams 1992). The population regression model assumed that
$Y=$ total student score in intermediate economics courses
$X_1=$ mathematics score on Scholastic Aptitude Test
$X_2=$ verbal score on Scholastic Aptitude Test
$X_3=$ grade in college algebra $(A=4, B=3, C=2$, $D=1$ )
$X_4=$ grade in college principles of economics course
$X_5=$ dummy variable taking the value 1 if the student is female and 0 if male
$X_6=$ dummy variable taking the value 1 if the instructor is male and 0 if female
$X_7=$ dummy variable taking the value 1 if the student and instructor are the same gender and 0 otherwise
This model was fitted to data on 262 students. Next we report $t$-ratios, so that $t_j$ is the ratio of the estimate of $\beta_j$ to its associated estimated standard error. These ratios are as follows:
$$
\begin{aligned}
& t_1=4.69, t_2=2.89, t_3=0.46, t_4=4.90, \\
& t_5=0.13, t_6=-1.08, t_7=0.88
\end{aligned}
$$
The objective of this study was to assess the impact of the gender of student and instructor on performance. Write a brief report outlining what has been learned about this issue.