data<-data.frame( A=gl(3,20,60), B=gl(4,5,60), Y=c(23, 25, 21, 14, 15, 20, 17, 11, 26, 21, 16, 19, 13, 16, 24, 20, 21, 18, 27, 24, 28, 30, 39, 17, 22, 26, 24, 21, 25, 26, 19, 18, 19, 20, 25, 26, 26, 28, 30, 23, 18, 15, 23, 18, 10, 21, 25, 12, 12, 22, 19, 23, 22, 14, 13, 22, 13, 12, 22, 19))data.aov <- aov(Y ~ A+B+A:B, data=tree)summary(tree.aov)[2]的结果是？