[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