Investigate the sensitivity of the regression results in Subsection XXXXXXXXXXto the range of values of the scores that are used in filtering the data. Try the effect of including data where: (a) the...

Investigate the sensitivity of the regression results in Subsection 13.2.2 to the range of values of the scores that are used in filtering the data. Try the effect of including data where: (a) the ratio of treatment to control numbers, as estimated from the density curve, is at least 1:40; (b) the ratio lies between 1:40 and 40; (c) the ratio is at least 1:10.