Question

7) Which variables are significant at 1% significance level? Why? 8) Which variables are insignificant at 20% significance level? Why? 9) Based on what you have learned, can you improve the model?

Number of obs = 141
F(5, 135) = 9.08
Prob > F = 0.0000
R-squared = 0.2355
Root MSE = .10796

------------------------------------------------------------------------------
| Robust
lcolGPA | Coef. Std. Err. t P>|t| [95% Conf. Interval]
-------------+----------------------------------------------------------------
lage | .1096206 .1829797 0.60 0.550 -.2522569 .4714981
hsGPA | .1421256 .0335665 4.23 0.000 .0757415 .2085098
ACT | .0042104 .0036565 1.15 0.252 -.003021 .0114418
male | .006346 .0194837 0.33 0.745 -.0321867 .0448788
skipped | -.0272508 .008722 -3.12 0.002 -.0445003 -.0100013
_cons | .2178343 .6002111 0.36 0.717 -.9691987 1.404867
------------------------------------------------------------------------------

Answer 1

7) Which variables are significant at 1% significance level?

alpha=0.01

hsGPA ,p=0.000 ,p<0.01,hsGPA is significant variable

skipped ,p=0.002 ,p<0.01,skipped is signiifcant variable

hsGPA and skipped variables are significant at 1% level

Which variables are insignificant at 20% significance level? Why?

alpha=0.20

For ACT,p=0.20,p>=.0.20,ACT is not a significant variable

For male ,p=0.745 ,p>0.20,is not a significant variable

For lage ,p=0.550,p>0.20,lage is not a significant variable

ACT male are not significant at 20% significance level.