expected frequencies

Expected frequencies are calculated based on a theoretical model or assumptions about the data. This is in contrast to the actual observed frequencies based on some form of empirical study or observation.

For example, if after user testing of new software we had 70 out of hundred participants who were novice and half of all participants commited some form of error, then the expected frequency, assuming no relationship between experience and performance, would be 35 novice participants commiting an error.