Reconsider Exercise 2.13, which was based on the experiment with small classes for primary school students conducted in Tennessee beginning in 1985. Data for the kindergarten classes is contained in the data file star.dat.

(a) Using children who are in either a regular-sized class or a small class, estimate the regression model explaining students’ combined aptitude scores as a function of class size, TOTALSCORE ¼ b1 þ b2SMALL þ

e. Test the null hypothesis that b2 is zero, or negative, against the alternative that this coefficient is positive.

Use the 5% level of significance. Compute the p-value of this test, and show its value in a sketch. Discuss the social importance of this finding.

(b) For the model in part (a), construct a 95% interval estimate of b2 and discuss.

(c) Repeat part

(a) using dependent variables READSCORE and MATHSCORE. Do you observe any differences?

(d) Using children who are in either a regular-sized class or a regular-sized class with a teacher aide, estimate the regression model explaining students’ combined aptitude scores as a function of the presence or absence of a teacher aide, TOTALSCORE ¼ g1 þ g2AIDE þ

e. Test the null hypothesis that g2 is zero or negative against the alternative that this coefficient is positive. Use the 5% level of significance. Discuss the importance of this finding.

(e) For the model in part (d), construct a 95% interval estimate of g2 and discuss.

(f) Repeat part

(d) using dependent variables READSCORE and MATHSCORE.

Do you observe any differences?