In recent years, the percentage of students leaving XYZ college at the end of the first year has increased significantly. In 2019, XYZ started a two-week orientation program to help first-year students adjust to campus life. If it has a positive effect on retention, they will consider this program a requirement for all first-year students. XYZ administration also suspects that students with lower GPAs have a high probability of leaving XYZ at the end of their first year. In order to investigate the relation between GPA (X1), Orientation Program (X2), and their retention, management advised to apply logistic regression. For this study, management selected a sample of 100 students from the past year and observed the results. Answer the questions which are followed by the R output:
Call: glm(formula = Y ~ X1 + X2, family = binomial, data = LR)
Deviance Residuals:
Min 1Q Median 3Q Max
-1.9610 -0.4828 0.2848 0.5980 1.8154
Coefficients:
Estimate Std. Error z value Pr(>|z|)
(Intercept) -6.8926 1.7472 -3.945 7.98e-05 ***
X1 2.5388 0.6729 3.773 0.000161 ***
X2 1.5608 0.5631 2.772 0.005579 **
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Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
(Dispersion parameter for binomial family taken to be 1)
Null deviance: 128.207 on 99 degrees of freedom
Residual deviance: 80.338 on 97 degrees of freedom
AIC: 86.338
Number of Fisher Scoring iterations: 5
(a) Write the logistic regression equation relating X1 and X2 to Y.
(b) Compute the estimated logit for independent variable X1 ,X2
(c) Comment on the overall signicance of the model? Justify by calculating Corresponding G-statistic value
(d) Comment on the individual significance of the model?
(e) What is the estimated odds ratio for the both GPA, Orientation Program?
Comment on these values Would you recommend making the orientation program a required activity? Why or why not?