> package <- factor(package) > > bacteria package logcount 1 1 7.66 2 1 6.98 3 1 7.80 4 2 5.26 5 2 5.44 6 2 5.80 7 3 7.41 8 3 7.33 9 3 7.04 10 4 3.51 11 4 2.91 12 4 3.66 > > contrasts(package) <- cbind(c(3,-1,-1,-1),c(0,2,-1,-1),c(0,0,1,-1)) > > contrasts(package) [,1] [,2] [,3] 1 3 0 0 2 -1 2 0 3 -1 -1 1 4 -1 -1 -1 > > package.mod <- aov(logcount~package) > > summary.lm(package.mod) Call: aov(formula = logcount ~ package) Residuals: Min 1Q Median 3Q Max -0.500 -0.225 0.110 0.210 0.320 Coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) 5.90000 0.09826 60.047 6.57e-12 *** package1 0.52667 0.05673 9.284 1.47e-05 *** package2 0.06333 0.08023 0.789 0.453 package3 1.95000 0.13895 14.033 6.45e-07 *** --- Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 Residual standard error: 0.3404 on 8 degrees of freedom Multiple R-squared: 0.9726, Adjusted R-squared: 0.9623 F-statistic: 94.58 on 3 and 8 DF, p-value: 1.376e-06 >