Alas, no one answered my last post about my problem of doing bwplot. I think my problem is related to the fact that there is a value missing in my data: levels(as.factor(gdf$OnHour)) [1] "0" "1" "2" "4" "5" "6" "7" "8" "9" "10" "11" "12" "13" "14" "15" [16] "16" "17" "18" "19" "20" "21" "22" "23" Notice that "3" is missing. But I really needthe plot on an x-axis going from 0-23 for every hour because different data sets are missing different hours, and I need to be able to compare the plots. To convert OnHour (an integer) to a factor, I did mdf$OnHFact = factor(mdf$OnHour, levels=seq(0,23), labels=as.character(seq(0,23)), exclude=NULL, ordered=TRUE) So, how do I get bwplot to skip the missing 3 am data value and put the boxes on their correct locations? Thanks, Jim