MTB > print c1-c3 ROW C1 C2 C3 1 5 20 1 2 10 23 1 3 12 30 1 4 9 25 1 5 23 34 1 6 21 40 1 7 14 27 1 8 18 38 1 9 6 24 1 10 13 31 1 11 7 19 0 12 12 26 0 13 27 33 0 14 24 35 0 15 18 30 0 16 22 31 0 17 26 34 0 18 21 28 0 19 14 23 0 20 9 22 0 MTB > let c4 = c1*c3 MTB > describe c1-c4 N MEAN MEDIAN TRMEAN STDEV SEMEAN C1 20 15.55 14.00 15.50 6.92 1.55 C2 20 28.65 29.00 28.56 5.93 1.33 C3 20 0.500 0.500 0.500 0.513 0.115 C4 20 6.55 2.50 6.00 7.90 1.77 MIN MAX Q1 Q3 C1 5.00 27.00 9.25 21.75 C2 19.00 40.00 23.25 33.75 C3 0.000 1.000 0.000 1.000 C4 0.00 23.00 0.00 12.75 MTB > describe c1-c2; SUBC> by c3. C3 N MEAN MEDIAN TRMEAN STDEV SEMEAN C1 0 10 18.00 19.50 18.25 7.15 2.26 1 10 13.10 12.50 12.88 6.05 1.91 C2 0 10 28.10 29.00 28.38 5.47 1.73 1 10 29.20 28.50 29.00 6.61 2.09 C3 MIN MAX Q1 Q3 C1 0 7.00 27.00 11.25 24.50 1 5.00 23.00 8.25 18.75 C2 0 19.00 35.00 22.75 33.25 1 20.00 40.00 23.75 35.00 MTB > dotplot c2; SUBC> by c3; SUBC> same. C3 0 . . . . . . . . . . -----+---------+---------+---------+---------+---------+-C2 C3 1 . . . . . . . . . . -----+---------+---------+---------+---------+---------+-C2 20.0 24.0 28.0 32.0 36.0 40.0 MTB > regress c2 2 c3 c1 The regression equation is C2 = 13.2 + 5.15 C3 + 0.827 C1 Predictor Coef Stdev t-ratio p Constant 13.205 1.917 6.89 0.000 C3 5.155 1.288 4.00 0.001 C1 0.82748 0.09550 8.66 0.000 s = 2.682 R-sq = 81.7% R-sq(adj) = 79.6% Analysis of Variance SOURCE DF SS MS F p Regression 2 546.23 273.11 37.96 0.000 Error 17 122.32 7.20 Total 19 668.55 SOURCE DF SEQ SS C3 1 6.05 C1 1 540.18 MTB > regress c2 3 c3 c1 c4 The regression equation is C2 = 15.1 + 1.31 C3 + 0.722 C1 + 0.254 C4 Predictor Coef Stdev t-ratio p Constant 15.109 2.351 6.43 0.000 C3 1.314 3.131 0.42 0.680 C1 0.7217 0.1222 5.90 0.000 C4 0.2536 0.1893 1.34 0.199 s = 2.622 R-sq = 83.5% R-sq(adj) = 80.5% Analysis of Variance SOURCE DF SS MS F p Regression 3 558.57 186.19 27.09 0.000 Error 16 109.98 6.87 Total 19 668.55 SOURCE DF SEQ SS C3 1 6.05 C1 1 540.18 C4 1 12.34 Unusual Observations Obs. C3 C2 Fit Stdev.Fit Residual St.Resid 5 1.00 34.000 38.856 1.654 -4.856 -2.39R R denotes an obs. with a large st. resid. MTB > ancova c2 = c3; SUBC> covariates c1. Factor Levels Values C3 2 0 1 Analysis of Covariance for C2 Source DF ADJ SS MS F P Covariates 1 540.18 540.18 75.07 0.000 C3 1 115.31 115.31 16.03 0.001 Error 17 122.32 7.20 Total 19 668.55 Covariate Coeff Stdev t-value P C1 0.8275 0.0955 8.665 0.000