Just to buy into the argument, when talking of data, we usually mean a set of data (the word set is implied) and set is singular. So when Dilbert says "that (set of) data IS wrong" he is grammatically correct. Naturally, the UNION of the sets of data can be averaged.
Hi, I am the CRS database administrator. I'm pretty sure that the CRS and SIBS databases can be multiplied, but I know for sure that there is NO WAY the DATA/DATUM can be averaged ! ;)
As I'm in the middle of the most boring psychology assignment I've ever had the misfortune to stumble across, complete with converting Pearson's R to z scores in order to compare them to another score (unofficial that was designed by the Psych dept) from an unrelated test that has nothing to do with the other two (no I'm not kidding), this treat of a strip is just in time!