[Stata Program] input id ability social contrib receive ach 161 .740000 1.000000 1.000000 2.333333 1.000000 164 .780000 1.000000 .000000 2.200000 .960000 159 .670000 1.000000 1.000000 2.500000 .950000 196 .740000 2.000000 2.000000 1.428571 .930000 189 .770000 3.000000 1.000000 1.666667 .920000 191 .800000 1.000000 6.000000 1.666667 .915000 334 .870000 9.000000 15.00000 .000000 .915000 173 .810000 1.000000 3.000000 1.250000 .910000 131 .750000 1.000000 8.000000 1.571429 .890000 214 .700000 3.000000 3.000000 3.000000 .885000 180 .760000 .000000 3.000000 1.000000 .880000 152 .800000 3.000000 7.000000 .666667 .875000 336 .670000 10.00000 5.000000 1.300000 .860000 188 .670000 3.000000 .000000 1.333333 .850000 337 .670000 9.000000 8.000000 -.400000 .850000 172 .650000 5.000000 2.000000 1.545455 .850000 186 .830000 3.000000 2.000000 .166667 .840000 209 .870000 5.000000 3.000000 1.000000 .833810 201 .780000 15.00000 6.000000 .000000 .830000 133 .680000 2.000000 6.000000 .578947 .825000 210 .690000 3.000000 .000000 1.500000 .810000 303 .880000 7.000000 12.00000 .285714 .935000 167 .730000 1.000000 7.000000 1.333333 .930000 333 .760000 1.000000 3.000000 1.142857 .890000 144 .740000 8.000000 3.000000 1.000000 .885000 207 .860000 .000000 6.000000 .900000 .885000 255 .700000 .000000 8.000000 1.428571 .885000 175 .640000 .000000 4.000000 1.571429 .860000 143 .730000 11.00000 4.000000 1.500000 .860000 347 .920000 .000000 7.000000 1.250000 .850000 241 .670000 .000000 10.00000 .687500 .840000 135 .790000 7.000000 8.000000 1.000000 .835000 244 .650000 .000000 4.000000 1.000000 .835000 262 .900000 .000000 8.000000 .333333 .820000 297 .750000 .000000 3.000000 .600000 .820000 341 .660000 .000000 5.000000 2.000000 .820000 305 .620000 .000000 3.000000 1.625000 .815000 332 .640000 .000000 3.000000 1.000000 .815000 193 .720000 4.000000 17.00000 1.428571 .770000 148 .800000 6.000000 8.000000 .666667 .740000 274 .670000 18.00000 10.00000 .000000 .740000 308 .670000 .000000 9.000000 1.000000 .735000 156 .790000 4.000000 14.00000 .076923 .725000 136 .690000 5.000000 16.00000 .857143 .700000 272 .730000 3.000000 9.000000 .800000 .700000 216 .690000 14.00000 27.00000 .363636 .680000 247 .790000 .000000 8.000000 .250000 .675000 150 .650000 5.000000 4.000000 .625000 .670000 220 .700000 18.00000 7.000000 .428571 .670000 259 .886667 .000000 8.000000 .666667 .670000 228 .670000 13.00000 7.000000 .600000 .645000 357 .590000 8.000000 14.00000 .421053 .645000 383 .610000 3.000000 15.00000 .294118 .625000 232 .700000 1.000000 19.00000 .800000 .600000 275 .590000 .000000 9.000000 .666667 .600000 338 .630000 12.00000 21.00000 .000000 .465000 end summarize ach ability receive contrib social correlate ach ability receive contrib social regress ach ability sw regress ach ability receive contrib social, beta pe(.05) lockterm1 test receive contrib regress ach ability receive contrib social vif test social [Stata Output] summarize ach ability receive contrib social Variable | Obs Mean Std. Dev. Min Max -------------+----------------------------------------------------- ach | 56 .8073895 .1101722 .465 1 ability | 56 .7306548 .0826076 .59 .92 receive | 56 .9805444 .688402 -.4 3 contrib | 56 7.178571 5.608783 0 27 social | 56 4.107143 4.867998 0 18 correlate ach ability receive contrib social (obs=56) | ach ability receive contrib social -------------+--------------------------------------------- ach | 1.0000 ability | 0.3760 1.0000 receive | 0.5322 -0.1067 1.0000 contrib | -0.6205 -0.0879 -0.5246 1.0000 social | -0.3068 -0.1230 -0.4416 0.3429 1.0000 regress ach ability Source | SS df MS Number of obs = 56 -------------+------------------------------ F( 1, 54) = 8.89 Model | .094366369 1 .094366369 Prob > F = 0.0043 Residual | .573218887 54 .010615165 R-squared = 0.1414 -------------+------------------------------ Adj R-squared = 0.1255 Total | .667585256 55 .012137914 Root MSE = .10303 ------------------------------------------------------------------------------ ach | Coef. Std. Err. t P>|t| [95% Conf. Interval] -------------+---------------------------------------------------------------- ability | .5014267 .1681753 2.98 0.004 .1642555 .8385978 _cons | .4410197 .123647 3.57 0.001 .1931224 .688917 ------------------------------------------------------------------------------ sw regress ach ability receive contrib social, beta pe(.05) lockterm1 begin with term 1 model p = 0.0000 < 0.0500 adding contrib p = 0.0012 < 0.0500 adding receive Source | SS df MS Number of obs = 56 -------------+------------------------------ F( 3, 52) = 24.21 Model | .389060023 3 .129686674 Prob > F = 0.0000 Residual | .278525233 52 .005356254 R-squared = 0.5828 -------------+------------------------------ Adj R-squared = 0.5587 Total | .667585256 55 .012137914 Root MSE = .07319 ------------------------------------------------------------------------------ ach | Coef. Std. Err. t P>|t| Beta -------------+---------------------------------------------------------------- ability | .5070472 .1219206 4.16 0.000 .380186 contrib | -.0077676 .0020971 -3.70 0.000 -.3954446 receive | .0584736 .0171179 3.42 0.001 .3653677 _cons | .4353376 .0990279 4.40 0.000 . ------------------------------------------------------------------------------ test receive contrib ( 1) receive = 0.0 ( 2) contrib = 0.0 F( 2, 52) = 27.51 Prob > F = 0.0000 regress ach ability receive contrib social Source | SS df MS Number of obs = 56 -------------+------------------------------ F( 4, 51) = 17.94 Model | .39024775 4 .097561937 Prob > F = 0.0000 Residual | .277337506 51 .00543799 R-squared = 0.5846 -------------+------------------------------ Adj R-squared = 0.5520 Total | .667585256 55 .012137914 Root MSE = .07374 ------------------------------------------------------------------------------ ach | Coef. Std. Err. t P>|t| [95% Conf. Interval] -------------+---------------------------------------------------------------- ability | .516964 .1246665 4.15 0.000 .2666856 .7672424 receive | .0615114 .0184322 3.34 0.002 .0245073 .0985156 contrib | -.007884 .0021277 -3.71 0.000 -.0121555 -.0036125 social | .0010914 .0023353 0.47 0.642 -.0035969 .0057796 _cons | .4214662 .1041016 4.05 0.000 .2124735 .6304588 ------------------------------------------------------------------------------ vif Variable | VIF 1/VIF -------------+---------------------- receive | 1.63 0.614097 contrib | 1.44 0.694261 social | 1.31 0.765071 ability | 1.07 0.932259 -------------+---------------------- Mean VIF | 1.36 test social ( 1) social = 0.0 F( 1, 51) = 0.22 Prob > F = 0.6422