[Stata Program] use http://www.gseis.ucla.edu/courses/data/immersion generate schdum1 = (school==12) generate schdum2 = (school==14) generate inter = prelang*pgm corr reading pgm sex prelang premath absent preschl books parlang momed daded regress reading schdum1 schdum2 pgm prelang test schdum1 schdum2 regress reading pgm regress reading prelang pgm regress reading prelang pgm inter tabulate pgm, summ (reading) tabulate pgm, summ (prelang) [Stata Program] use http://www.gseis.ucla.edu/courses/data/immersion generate schdum1 = (school==12) generate schdum2 = (school==14) generate inter = prelang*pgm corr reading pgm sex prelang premath absent preschl books parlang momed daded (obs=143) | reading pgm sex prelang premath absent preschl books parlang -------------+--------------------------------------------------------------------------------- reading | 1.0000 pgm | 0.2209 1.0000 sex | -0.0068 0.2069 1.0000 prelang | 0.2098 0.0671 0.1936 1.0000 premath | 0.1058 0.1348 0.0502 0.4062 1.0000 absent | -0.0273 0.0428 -0.0162 -0.0941 -0.0468 1.0000 preschl | -0.0856 0.0865 -0.0550 -0.1838 -0.0271 0.0941 1.0000 books | 0.1073 -0.1610 0.0457 0.1108 0.0338 0.0053 -0.3068 1.0000 parlang | 0.0451 -0.0172 0.0764 0.1127 0.0368 0.1565 -0.2080 0.1385 1.0000 momed | -0.0073 0.0625 0.0566 0.0287 0.0776 0.0734 -0.2404 0.3538 0.0826 daded | -0.0140 -0.1150 0.0521 0.1628 0.2078 -0.0600 -0.3993 0.4351 0.1872 | momed daded -------------+------------------ momed | 1.0000 daded | 0.5009 1.0000 regress reading schdum1 schdum2 pgm prelang Source | SS df MS Number of obs = 143 -------------+------------------------------ F( 4, 138) = 4.18 Model | 12607.0394 4 3151.75985 Prob > F = 0.0032 Residual | 104082.205 138 754.218879 R-squared = 0.1080 -------------+------------------------------ Adj R-squared = 0.0822 Total | 116689.245 142 821.755245 Root MSE = 27.463 ------------------------------------------------------------------------------ reading | Coef. Std. Err. t P>|t| [95% Conf. Interval] -------------+---------------------------------------------------------------- schdum1 | -5.901005 6.4485 -0.92 0.362 -18.65165 6.849636 schdum2 | -12.23476 6.879354 -1.78 0.078 -25.83733 1.367808 pgm | 6.752536 2.675891 2.52 0.013 1.461487 12.04359 prelang | .2338472 .0924057 2.53 0.013 .0511332 .4165612 _cons | 178.4792 15.74787 11.33 0.000 147.3409 209.6176 ------------------------------------------------------------------------------ test schdum1 schdum2 ( 1) schdum1 = 0.0 ( 2) schdum2 = 0.0 F( 2, 138) = 1.63 Prob > F = 0.1996 regress reading pgm Source | SS df MS Number of obs = 143 -------------+------------------------------ F( 1, 141) = 7.23 Model | 5693.25112 1 5693.25112 Prob > F = 0.0080 Residual | 110995.994 141 787.205629 R-squared = 0.0488 -------------+------------------------------ Adj R-squared = 0.0420 Total | 116689.245 142 821.755245 Root MSE = 28.057 ------------------------------------------------------------------------------ reading | Coef. Std. Err. t P>|t| [95% Conf. Interval] -------------+---------------------------------------------------------------- pgm | 6.926803 2.575709 2.69 0.008 1.834803 12.0188 _cons | 210.291 4.714075 44.61 0.000 200.9716 219.6104 ------------------------------------------------------------------------------ regress reading prelang pgm Source | SS df MS Number of obs = 143 -------------+------------------------------ F( 2, 140) = 6.67 Model | 10147.9507 2 5073.97533 Prob > F = 0.0017 Residual | 106541.294 140 761.009244 R-squared = 0.0870 -------------+------------------------------ Adj R-squared = 0.0739 Total | 116689.245 142 821.755245 Root MSE = 27.586 ------------------------------------------------------------------------------ reading | Coef. Std. Err. t P>|t| [95% Conf. Interval] -------------+---------------------------------------------------------------- prelang | .22072 .0912278 2.42 0.017 .0403576 .4010823 pgm | 6.514449 2.538218 2.57 0.011 1.496256 11.53264 _cons | 174.4681 15.5148 11.25 0.000 143.7945 205.1417 ------------------------------------------------------------------------------ regress reading prelang pgm inter Source | SS df MS Number of obs = 143 -------------+------------------------------ F( 3, 139) = 4.61 Model | 10560.8745 3 3520.2915 Prob > F = 0.0042 Residual | 106128.37 139 763.513455 R-squared = 0.0905 -------------+------------------------------ Adj R-squared = 0.0709 Total | 116689.245 142 821.755245 Root MSE = 27.632 ------------------------------------------------------------------------------ reading | Coef. Std. Err. t P>|t| [95% Conf. Interval] -------------+---------------------------------------------------------------- prelang | .1030193 .1842973 0.56 0.577 -.2613692 .4674079 pgm | -5.597256 16.66451 -0.34 0.737 -38.54596 27.35145 inter | .0726358 .0987698 0.74 0.463 -.1226496 .2679212 _cons | 193.9781 30.74598 6.31 0.000 133.1878 254.7683 ------------------------------------------------------------------------------ tabulate pgm, summ (reading) | Summary of reading pgm | Mean Std. Dev. Freq. ------------+------------------------------------ 1 | 217.21782 28.549817 101 3 | 231.07143 26.817716 42 ------------+------------------------------------ Total | 221.28671 28.666274 143 tabulate pgm, summ (prelang) | Summary of prelang pgm | Mean Std. Dev. Freq. ------------+------------------------------------ 1 | 164.16832 25.114565 101 3 | 167.90476 26.302935 42 ------------+------------------------------------ Total | 165.26573 25.433412 143