## Quick Reference

Sources of bias include (a) bias in sampling, when members of the sample are not fully representative of the population being studied; (b) nonresponse bias in sample surveys, when an appreciable proportion of those questioned fail to reply; (c) question bias, a tendency for the wording of the question to invite an incorrect reply; (d) interviewer bias, a problem of personal interviewing when respondents try to reply in the way the interviewer is thought to expect.

A narrower definition of bias in statistical analysis (see statistical methods) is the difference between the mean of an estimating formula and the true value of the quantity being estimated. The estimatefor the variance of a population is biased, but is unbiased when *n* is replaced by (*n*–1).

**excess factor**) See floating-point notation.

**From:**
bias
in
A Dictionary of Computing »

*Subjects:*
Computing.