clear all
set more off

/* Download data */
shell curl -o final4.dta http://economics.mit.edu/files/1359
shell curl -o final5.dta http://economics.mit.edu/files/1358

/*---------*/
/* Grade 4 */
/*---------*/
/* Import data */
use "final4.dta", clear

/* Restrict sample */
keep if 1 < classize & classize < 45 & c_size > 5

/* Find means class size by grade size */
collapse classize, by(c_size)

/* Plot the actual and predicted class size based on grade size */
graph twoway (line classize c_size, lcolor(black))                              ///
             (function y = x / (floor((x - 1)/40) + 1),                         ///
                    range(1 220) lpattern(dash) lcolor(black)),                 ///
                xlabel(20(20)220)                                               ///
                title("B. Fourth grade")                                        ///
                ytitle("Class size")                                            ///
                xtitle("Enrollment count")                                      ///
                legend(label(1 "Actual class size") label(2 "Maimonides Rule")) ///
                scheme(s1mono)                                                  ///
                saving(fourthgrade.gph, replace)

/*---------*/
/* Grade 5 */
/*---------*/
/* Import data */
use "final5.dta", clear

/* Restrict sample */
keep if 1 < classize & classize < 45 & c_size > 5

/* Find means class size by grade size */
collapse classize, by(c_size)

/* Plot the actual and predicted class size based on grade size */
graph twoway (line classize c_size, lcolor(black))                               ///
             (function y = x / (floor((x - 1)/40) + 1),                          ///
                    range(1 220) lpattern(dash) lcolor(black)),                  ///
                xlabel(20(20)220)                                                ///
                title("A. Fifth grade")                                          ///
                ytitle("Class size")                                             ///
                xtitle("Enrollment count")                                       ///
                legend(label(1 "Actual class size") label(2 "Maimonides Rule"))  ///
                scheme(s1mono)                                                   ///
                saving(fifthgrade.gph, replace)

/* Combine graphs */
graph combine fifthgrade.gph fourthgrade.gph,   ///
    col(1)                                      ///
    xsize(4) ysize(6)                           ///
    graphregion(margin(zero))                   ///
    scheme(s1mono)
graph export "Figure 6-2-1-Stata.png", replace

/* End of file */
exit