. * do-file for lecture 5b (part) of VHM 802/812, Winter 2014 . version 13 . set more off . cd "f:\vhm\vhm802\data_stata" f:\vhm\vhm802\data_stata . . * conditional logistic regression . use sal_outbrk.dta, clear . summarize Variable | Obs Mean Std. Dev. Min Max -------------+-------------------------------------------------------- match_grp | 112 28.63393 17.16271 1 59 date | 100 13426.43 6.449892 13418 13463 age | 97 28.06359 15.94086 2.532512 64.43532 gender | 112 .4732143 .501526 0 1 casecontrol | 112 .3482143 .4785455 0 1 -------------+-------------------------------------------------------- eatbeef | 106 .6698113 .472515 0 1 eatpork | 106 .7924528 .4074773 0 1 eatveal | 107 .0654206 .2484301 0 1 eatlamb | 109 .0366972 .1888859 0 1 eatpoul | 105 .3238095 .4701726 0 1 -------------+-------------------------------------------------------- eatcold | 111 .972973 .1628976 0 1 eatveg | 109 .9266055 .2619875 0 1 eatfruit | 109 .8348624 .3730197 0 1 eateggs | 103 .7669903 .4248156 0 1 slt_a | 112 .4821429 .5019268 0 1 -------------+-------------------------------------------------------- dlr_a | 99 .2121212 .4108907 0 1 dlr_b | 99 .0707071 .2576394 0 1 . browse match_grp age gender casecontrol eatpork eatpoul eatbeef eateggs slt_a dlr_a . list match_grp age gender casecontrol eatbeef eatpork slt_a dlr_a if match_grp==23 +------------------------------------------------------------------------+ | match_~p age gender caseco~l eatbeef eatpork slt_a dlr_a | |------------------------------------------------------------------------| 39. | 23 . Male case no yes yes no | 40. | 23 . Male contr yes yes yes no | 41. | 23 . Male contr no yes no no | +------------------------------------------------------------------------+ . . * Mantel-Haenszel statistics for binary exposures . cc casecontrol eatpork, by(match_grp) nohom Matching group | OR [95% Conf. Interval] M-H Weight -----------------+------------------------------------------------- 1 | . 0 . 0 (exact) 2 | . . . 0 (exact) 3 | 0 0 . .3333333 (exact) 4 | 0 0 . .6666667 (exact) 5 | . 0 . 0 (exact) 7 | . 0 . 0 (exact) 9 | . 0 . 0 (exact) 11 | . 0 . 0 (exact) 12 | 0 0 . .6666667 (exact) 13 | . 0 . 0 (exact) 15 | . 0 . 0 (exact) 16 | . 0 . 0 (exact) 22 | . 0 . 0 (exact) 23 | . 0 . 0 (exact) 24 | . 0 . 0 (exact) 25 | . 0 . 0 (exact) 26 | . . . 0 (exact) 27 | . 0 . 0 (exact) 28 | . 0 . 0 (exact) 29 | . 0 . 0 (exact) 30 | . 0 . 0 (exact) 31 | . 0 . 0 (exact) 32 | . 0 . 0 (exact) 33 | . 0 . 0 (exact) 34 | . 0 . 0 (exact) 36 | . 0 . 0 (exact) 39 | . 0 . 0 (exact) 42 | . 0 . 0 (exact) 43 | . 0 . 0 (exact) 44 | 0 0 . .6666667 (exact) 45 | . . . 0 (exact) 46 | . 0 . 0 (exact) 49 | . 0 . 0 (exact) 50 | . 0 . 0 (exact) 52 | . 0 . 0 (exact) 53 | . 0 . 0 (exact) 55 | . 0 . 0 (exact) 58 | . . . 0 (exact) 59 | . . . 0 (exact) -----------------+------------------------------------------------- Crude | 2.5 .7240032 11.00641 (exact) M-H combined | 2.142857 .6900548 6.654307 Test that combined OR = 1: Mantel-Haenszel chi2(1) = 1.86 Pr>chi2 = 0.1732 . cc casecontrol eatpork /* incorrect 2*2-table analysis */ Proportion | Exposed Unexposed | Total Exposed -----------------+------------------------+------------------------ Cases | 30 4 | 34 0.8824 Controls | 54 18 | 72 0.7500 -----------------+------------------------+------------------------ Total | 84 22 | 106 0.7925 | | | Point estimate | [95% Conf. Interval] |------------------------+------------------------ Odds ratio | 2.5 | .7240032 11.00641 (exact) Attr. frac. ex. | .6 | -.3812093 .9091439 (exact) Attr. frac. pop | .5294118 | +------------------------------------------------- chi2(1) = 2.46 Pr>chi2 = 0.1168 . cc casecontrol eateggs, by(match_grp) nohom Matching group | OR [95% Conf. Interval] M-H Weight -----------------+------------------------------------------------- 1 | . 0 . 0 (exact) 2 | . . . 0 (exact) 3 | . . . 0 (exact) 4 | . . . 0 (exact) 5 | . 0 . 0 (exact) 7 | . 0 . 0 (exact) 9 | . 0 . 0 (exact) 11 | . 0 . 0 (exact) 12 | 0 0 . .6666667 (exact) 13 | 0 0 . .3333333 (exact) 15 | . . . 0 (exact) 16 | . 0 . 0 (exact) 22 | . 0 . 0 (exact) 23 | . 0 . 0 (exact) 24 | . 0 . 0 (exact) 25 | . 0 . 0 (exact) 26 | . 0 . 0 (exact) 27 | . . . 0 (exact) 28 | . 0 . 0 (exact) 29 | . 0 . 0 (exact) 30 | . 0 . 0 (exact) 31 | . 0 . 0 (exact) 32 | . 0 . 0 (exact) 33 | 0 0 . .3333333 (exact) 34 | . 0 . 0 (exact) 36 | . . . 0 (exact) 39 | . 0 . 0 (exact) 42 | . . . 0 (exact) 43 | . 0 . 0 (exact) 44 | . 0 . 0 (exact) 45 | . 0 . 0 (exact) 46 | . 0 . 0 (exact) 49 | . 0 . 0 (exact) 50 | . 0 . 0 (exact) 52 | . 0 . 0 (exact) 53 | . . . 0 (exact) 55 | . . . 0 (exact) 58 | . 0 . 0 (exact) 59 | . 0 . 0 (exact) -----------------+------------------------------------------------- Crude | 1.973077 .616499 7.467738 (exact) M-H combined | 2.75 .6671433 11.33565 Test that combined OR = 1: Mantel-Haenszel chi2(1) = . Pr>chi2 = . . cc casecontrol slt_a, by(match_grp) nohom Matching group | OR [95% Conf. Interval] M-H Weight -----------------+------------------------------------------------- 1 | . 0 . 0 (exact) 2 | 0 0 . .6666667 (exact) 3 | 0 0 . .3333333 (exact) 4 | . 0 . 0 (exact) 5 | . 0 . 0 (exact) 7 | . 0 . 0 (exact) 9 | 0 0 . .6666667 (exact) 11 | . 0 . 0 (exact) 12 | . . . 0 (exact) 13 | . 0 . 0 (exact) 15 | . 0 . 0 (exact) 16 | . . . 0 (exact) 22 | . 0 . 0 (exact) 23 | . 0 . 0 (exact) 24 | . 0 . 0 (exact) 25 | 0 0 . .3333333 (exact) 26 | . 0 . 0 (exact) 27 | . . . 0 (exact) 28 | . . . 0 (exact) 29 | . . . 0 (exact) 30 | . 0 . 0 (exact) 31 | . 0 . 0 (exact) 32 | . 0 . 0 (exact) 33 | . 0 . 0 (exact) 34 | . . . 0 (exact) 36 | . 0 . 0 (exact) 39 | . 0 . 0 (exact) 42 | . . . 0 (exact) 43 | . 0 . 0 (exact) 44 | . 0 . 0 (exact) 45 | . 0 . 0 (exact) 46 | . 0 . 0 (exact) 49 | . 0 . 0 (exact) 50 | . 0 . 0 (exact) 52 | . 0 . 0 (exact) 53 | . 0 . 0 (exact) 55 | 0 0 . .5 (exact) 58 | . 0 . 0 (exact) 59 | . . . 0 (exact) -----------------+------------------------------------------------- Crude | 3.214286 1.323847 7.940837 (exact) M-H combined | 3.866667 1.445059 10.34637 Test that combined OR = 1: Mantel-Haenszel chi2(1) = 9.48 Pr>chi2 = 0.0021 . cc casecontrol dlr_a, by(match_grp) nohom Matching group | OR [95% Conf. Interval] M-H Weight -----------------+------------------------------------------------- 1 | . . . 0 (exact) 2 | . . . 0 (exact) 3 | . . . 0 (exact) 4 | . 0 . 0 (exact) 5 | . . . 0 (exact) 7 | . . . 0 (exact) 9 | . . . 0 (exact) 11 | . . . 0 (exact) 12 | . . . 0 (exact) 13 | . 0 . 0 (exact) 15 | . . . 0 (exact) 16 | . . . 0 (exact) 22 | . 0 . 0 (exact) 23 | . . . 0 (exact) 24 | . . . 0 (exact) 25 | . . . 0 (exact) 26 | . . . 0 (exact) 27 | . . . 0 (exact) 28 | . . . 0 (exact) 29 | . . . 0 (exact) 30 | . 0 . 0 (exact) 31 | . 0 . 0 (exact) 32 | . 0 . 0 (exact) 33 | . 0 . 0 (exact) 34 | . . . 0 (exact) 36 | . . . 0 (exact) 39 | . . . 0 (exact) 42 | . . . 0 (exact) 43 | . . . 0 (exact) 44 | . 0 . 0 (exact) 45 | . 0 . 0 (exact) 46 | . 0 . 0 (exact) 49 | 0 0 . .6666667 (exact) 50 | . 0 . 0 (exact) 52 | . . . 0 (exact) 53 | . . . 0 (exact) 55 | . . . 0 (exact) 58 | . 0 . 0 (exact) 59 | . . . 0 (exact) -----------------+------------------------------------------------- Crude | 4.140351 1.342934 12.8559 (exact) M-H combined | 7.75 1.203515 49.90588 Test that combined OR = 1: Mantel-Haenszel chi2(1) = . Pr>chi2 = . . . * univariate CLR (conditional logistic regression) . clogit casecontrol slt_a, group(match_grp) Iteration 0: log likelihood = -36.017955 Iteration 1: log likelihood = -35.82051 Iteration 2: log likelihood = -35.820042 Iteration 3: log likelihood = -35.820042 Conditional (fixed-effects) logistic regression Number of obs = 112 LR chi2(1) = 10.00 Prob > chi2 = 0.0016 Log likelihood = -35.820042 Pseudo R2 = 0.1225 ------------------------------------------------------------------------------ casecontrol | Coef. Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- slt_a | 1.485215 .5181015 2.87 0.004 .4697549 2.500676 ------------------------------------------------------------------------------ . clogit casecontrol slt_a, group(match_grp) or Iteration 0: log likelihood = -36.017955 Iteration 1: log likelihood = -35.82051 Iteration 2: log likelihood = -35.820042 Iteration 3: log likelihood = -35.820042 Conditional (fixed-effects) logistic regression Number of obs = 112 LR chi2(1) = 10.00 Prob > chi2 = 0.0016 Log likelihood = -35.820042 Pseudo R2 = 0.1225 ------------------------------------------------------------------------------ casecontrol | Odds Ratio Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- slt_a | 4.415916 2.287893 2.87 0.004 1.599602 12.19073 ------------------------------------------------------------------------------ . clogit casecontrol dlr_a, group(match_grp) /* note missing values of dlr_a */ note: 10 groups (16 obs) dropped because of all positive or all negative outcomes. Iteration 0: log likelihood = -26.449441 Iteration 1: log likelihood = -25.564131 Iteration 2: log likelihood = -25.56413 Conditional (fixed-effects) logistic regression Number of obs = 83 LR chi2(1) = 9.35 Prob > chi2 = 0.0022 Log likelihood = -25.56413 Pseudo R2 = 0.1546 ------------------------------------------------------------------------------ casecontrol | Coef. Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- dlr_a | 2.4749 1.064786 2.32 0.020 .3879573 4.561843 ------------------------------------------------------------------------------ . table match_grp casecont if dlr_a~=. /* 10 sets with no case or no controls */ ---------------------------- | Case-control Matching | status group | control case ----------+----------------- 1 | 2 1 2 | 2 3 | 2 1 4 | 2 1 5 | 2 1 7 | 1 1 9 | 2 1 11 | 2 1 12 | 2 13 | 2 1 15 | 1 1 16 | 1 1 22 | 2 1 23 | 2 1 24 | 2 1 25 | 2 1 26 | 2 1 27 | 2 28 | 2 1 29 | 2 30 | 2 1 31 | 2 1 32 | 1 1 33 | 2 1 34 | 1 36 | 2 1 39 | 2 1 42 | 2 43 | 1 44 | 2 1 45 | 2 1 46 | 1 49 | 2 1 50 | 2 1 52 | 2 1 53 | 2 1 55 | 1 58 | 2 1 59 | 2 ---------------------------- . clogit casecontrol eatpork, group(match_grp) /* note missing values of eatpork */ note: 5 groups (10 obs) dropped because of all positive or all negative outcomes. Iteration 0: log likelihood = -33.935682 Iteration 1: log likelihood = -33.924226 Iteration 2: log likelihood = -33.92422 Iteration 3: log likelihood = -33.92422 Conditional (fixed-effects) logistic regression Number of obs = 96 LR chi2(1) = 1.99 Prob > chi2 = 0.1582 Log likelihood = -33.92422 Pseudo R2 = 0.0285 ------------------------------------------------------------------------------ casecontrol | Coef. Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- eatpork | .7832009 .5874627 1.33 0.182 -.3682049 1.934607 ------------------------------------------------------------------------------ . clogit casecontrol eateggs, group(match_grp) /* note missing values of eateggs */ note: 7 groups (13 obs) dropped because of all positive or all negative outcomes. Iteration 0: log likelihood = -31.705811 Iteration 1: log likelihood = -31.640388 Iteration 2: log likelihood = -31.640261 Iteration 3: log likelihood = -31.640261 Conditional (fixed-effects) logistic regression Number of obs = 90 LR chi2(1) = 2.17 Prob > chi2 = 0.1412 Log likelihood = -31.640261 Pseudo R2 = 0.0331 ------------------------------------------------------------------------------ casecontrol | Coef. Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- eateggs | .9698158 .6979461 1.39 0.165 -.3981333 2.337765 ------------------------------------------------------------------------------ . . * multivariable CLR . clogit casecontrol slt_a dlr_a, group(match_grp) note: 10 groups (16 obs) dropped because of all positive or all negative outcomes. Iteration 0: log likelihood = -23.453038 Iteration 1: log likelihood = -22.838773 Iteration 2: log likelihood = -22.838098 Iteration 3: log likelihood = -22.838098 Conditional (fixed-effects) logistic regression Number of obs = 83 LR chi2(2) = 14.80 Prob > chi2 = 0.0006 Log likelihood = -22.838098 Pseudo R2 = 0.2447 ------------------------------------------------------------------------------ casecontrol | Coef. Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- slt_a | 1.471547 .6853288 2.15 0.032 .1283273 2.814767 dlr_a | 1.629739 1.103103 1.48 0.140 -.5323029 3.791781 ------------------------------------------------------------------------------ . estimates store full . clogit casecontrol slt_a if dlr_a~=., group(match_grp) note: 10 groups (16 obs) dropped because of all positive or all negative outcomes. Iteration 0: log likelihood = -24.38806 Iteration 1: log likelihood = -24.348329 Iteration 2: log likelihood = -24.348232 Iteration 3: log likelihood = -24.348232 Conditional (fixed-effects) logistic regression Number of obs = 83 LR chi2(1) = 11.78 Prob > chi2 = 0.0006 Log likelihood = -24.348232 Pseudo R2 = 0.1948 ------------------------------------------------------------------------------ casecontrol | Coef. Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- slt_a | 1.89557 .6441469 2.94 0.003 .6330655 3.158075 ------------------------------------------------------------------------------ . lrtest full /* LR-test gives lower P than Wald test */ Likelihood-ratio test LR chi2(1) = 3.02 (Assumption: . nested in full) Prob > chi2 = 0.0822 . clogit casecontrol slt_a eatpork, group(match_grp) note: 5 groups (10 obs) dropped because of all positive or all negative outcomes. Iteration 0: log likelihood = -29.752114 Iteration 1: log likelihood = -29.561902 Iteration 2: log likelihood = -29.561307 Iteration 3: log likelihood = -29.561307 Conditional (fixed-effects) logistic regression Number of obs = 96 LR chi2(2) = 10.72 Prob > chi2 = 0.0047 Log likelihood = -29.561307 Pseudo R2 = 0.1535 ------------------------------------------------------------------------------ casecontrol | Coef. Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- slt_a | 1.536735 .5772246 2.66 0.008 .4053956 2.668074 eatpork | .5658754 .6030214 0.94 0.348 -.6160248 1.747776 ------------------------------------------------------------------------------ . clogit casecontrol slt_a eateggs, group(match_grp) note: 7 groups (13 obs) dropped because of all positive or all negative outcomes. Iteration 0: log likelihood = -24.847337 Iteration 1: log likelihood = -24.412117 Iteration 2: log likelihood = -24.40982 Iteration 3: log likelihood = -24.409819 Conditional (fixed-effects) logistic regression Number of obs = 90 LR chi2(2) = 16.63 Prob > chi2 = 0.0002 Log likelihood = -24.409819 Pseudo R2 = 0.2540 ------------------------------------------------------------------------------ casecontrol | Coef. Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- slt_a | 2.289793 .7645301 3.00 0.003 .7913412 3.788244 eateggs | .9915344 .7623728 1.30 0.193 -.5026889 2.485758 ------------------------------------------------------------------------------ . clogit casecontrol slt_a##gender, group(match_grp) note: 1.gender omitted because of no within-group variance. Iteration 0: log likelihood = -35.894695 Iteration 1: log likelihood = -35.19821 Iteration 2: log likelihood = -35.197693 Iteration 3: log likelihood = -35.197693 Conditional (fixed-effects) logistic regression Number of obs = 112 LR chi2(2) = 11.24 Prob > chi2 = 0.0036 Log likelihood = -35.197693 Pseudo R2 = 0.1377 ------------------------------------------------------------------------------ casecontrol | Coef. Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- slt_a | yes | 1.063157 .6159625 1.73 0.084 -.1441072 2.270421 | gender | Female | 0 (omitted) | slt_a#gender | yes#Female | 1.28332 1.234781 1.04 0.299 -1.136806 3.703446 ------------------------------------------------------------------------------ . clogit casecontrol slt_a##c.age, group(match_grp) note: 3 groups (4 obs) dropped because of all positive or all negative outcomes. Iteration 0: log likelihood = -29.807362 Iteration 1: log likelihood = -29.446815 Iteration 2: log likelihood = -29.444699 Iteration 3: log likelihood = -29.444699 Conditional (fixed-effects) logistic regression Number of obs = 93 LR chi2(3) = 8.75 Prob > chi2 = 0.0328 Log likelihood = -29.444699 Pseudo R2 = 0.1294 ------------------------------------------------------------------------------ casecontrol | Coef. Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- slt_a | yes | 2.493701 1.259868 1.98 0.048 .0244059 4.962996 age | -2.997822 3.967855 -0.76 0.450 -10.77467 4.779031 | slt_a#c.age | yes | -.0466566 .0422594 -1.10 0.270 -.1294835 .0361703 ------------------------------------------------------------------------------ . . * OLR (ordinary logistic regression) - not recommended . logit casecontrol slt_a /* bias towards the null */ Iteration 0: log likelihood = -72.38943 Iteration 1: log likelihood = -68.28612 Iteration 2: log likelihood = -68.254451 Iteration 3: log likelihood = -68.254443 Iteration 4: log likelihood = -68.254443 Logistic regression Number of obs = 112 LR chi2(1) = 8.27 Prob > chi2 = 0.0040 Log likelihood = -68.254443 Pseudo R2 = 0.0571 ------------------------------------------------------------------------------ casecontrol | Coef. Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- slt_a | 1.167605 .4163185 2.80 0.005 .3516358 1.983574 _cons | -1.241713 .3148735 -3.94 0.000 -1.858854 -.6245725 ------------------------------------------------------------------------------ . * OLR with matching variables as confounders - validity unclear . logit casecontrol slt_a age gender Iteration 0: log likelihood = -62.833219 Iteration 1: log likelihood = -60.025885 Iteration 2: log likelihood = -60.009335 Iteration 3: log likelihood = -60.009333 Logistic regression Number of obs = 97 LR chi2(3) = 5.65 Prob > chi2 = 0.1301 Log likelihood = -60.009333 Pseudo R2 = 0.0449 ------------------------------------------------------------------------------ casecontrol | Coef. Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- slt_a | 1.021105 .4434945 2.30 0.021 .1518712 1.890338 age | .0012583 .0141469 0.09 0.929 -.0264691 .0289858 gender | .0997614 .4444179 0.22 0.822 -.7712817 .9708044 _cons | -1.23389 .5883852 -2.10 0.036 -2.387104 -.0806764 ------------------------------------------------------------------------------ . . * CLR diagnostics using add-on command clfit . clogit casecontrol slt_a, group(match_grp) Iteration 0: log likelihood = -36.017955 Iteration 1: log likelihood = -35.82051 Iteration 2: log likelihood = -35.820042 Iteration 3: log likelihood = -35.820042 Conditional (fixed-effects) logistic regression Number of obs = 112 LR chi2(1) = 10.00 Prob > chi2 = 0.0016 Log likelihood = -35.820042 Pseudo R2 = 0.1225 ------------------------------------------------------------------------------ casecontrol | Coef. Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- slt_a | 1.485215 .5181015 2.87 0.004 .4697549 2.500676 ------------------------------------------------------------------------------ . clfit, graph /* Stata add-on for CLR diagnostics */ Clogit model for casecontrol number of observations= 112 . * Stata 13 also gives the same diagnostics (+ more) with the predict command . predict p, p . predict pearson, residuals . sort _gdbeta match_grp casecontrol . list match_grp casecontrol slt_a _hat _d* _g* in -6/-1, sep(10) +-----------------------------------------------------------------------------------------+ | match_~p caseco~l slt_a _hat _dx2 _dbeta _gdx2 _gdbeta | |-----------------------------------------------------------------------------------------| 107. | 2 contr yes .00124723 .44970566 .00056159 9.0116723 .18386783 | 108. | 2 contr yes .00124723 .44970566 .00056159 9.0116723 .18386783 | 109. | 2 case no .02203069 8.112261 .18274466 9.0116723 .18386783 | 110. | 9 contr yes .00124723 .44970566 .00056159 9.0116723 .18386783 | 111. | 9 contr yes .00124723 .44970566 .00056159 9.0116723 .18386783 | 112. | 9 case no .02203069 8.112261 .18274466 9.0116723 .18386783 | +-----------------------------------------------------------------------------------------+ . * analysis without sets 2 & 9 . clogit casecontrol slt_a if match_grp~=2 & match_grp~=9, group(match_grp) Iteration 0: log likelihood = -31.242356 Iteration 1: log likelihood = -30.745445 Iteration 2: log likelihood = -30.744678 Iteration 3: log likelihood = -30.744678 Conditional (fixed-effects) logistic regression Number of obs = 106 LR chi2(1) = 15.75 Prob > chi2 = 0.0001 Log likelihood = -30.744678 Pseudo R2 = 0.2039 ------------------------------------------------------------------------------ casecontrol | Coef. Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- slt_a | 2.081011 .6328898 3.29 0.001 .8405703 3.321453 ------------------------------------------------------------------------------ . end of do-file . exit, clear