means of a column within groups of a data frame
John Sorkin wrote:
R 2.8.0 windows XP I would like to divide the rows of data frame into five groups and then get the mean of one column within the five groups. I have accomplished this using the code below, but I hope there is an easier way, i.e. some function that I can call # create five groups. cut(data$BMI,5) # get mean of AAMTCARE within each of the five groups mean(data[data[,"BMIcuts"]=="(13.3,21.9]","AAMTCARE"]) mean(data[data[,"BMIcuts"]=="(21.9,30.5]","AAMTCARE"]) mean(data[data[,"BMIcuts"]=="(30.5,39.1]","AAMTCARE"]) mean(data[data[,"BMIcuts"]=="(39.1,47.7]","AAMTCARE"]) mean(data[data[,"BMIcuts"]=="(47.7,56.3]","AAMTCARE"])
Hi John, Have a look at brkdn in the prettyR package. data$BMIcuts<-cut(data$BMI,5) brkdn(BMI~BMIcuts,data) Jim