Possible Duplicate:
Which is correct, “dataset” or “data set”?
When writing about sets of data produced and analysed for a scientific experiment, which of the two forms is most adequate for a piece of international scientific writing? Is it "datasets" or "data sets"?
Wikipedia suggests that either "dataset" or "data set" is acceptable.
Either is fine. Ngrams shows a preference for data set:
COCA shows 44 results for a data set, and 11 for a dataset, the earliest of which occurred in 2004.
The fact that data set is more common than dataset is due to the fact that dataset only recently became acceptable, as compared with the original and hence more longstanding data set.
