Standard error (of the mean)
The difference between an observed mean (of a sample of quantitative data) and the true mean. The latter could only be known if the data for the entire population could be collected instead of just a sample, which is usually impossible in ornithological studies, but statistical analysis of the data can suggest what the true mean might be, and can also provide 'confidence limits' which show, for example, that in 95% of cases such assessments of the mean will be correct.From Peter Weaver's Birdwatcher's Dictionary
Copyright © 1981 by Peter Weaver