unbiased measurement
21Opinion poll — An opinion poll, sometimes simply referred to as a poll is a survey of public opinion from a particular sample. Opinion polls are usually designed to represent the opinions of a population by conducting a series of questions and then… …
22Stereology — (from Greek stereos = solid) was originally defined as the spatial interpretation of sections . It is an interdisciplinary field that is largely concerned with the three dimensional interpretation of planar sections of materials or tissues. It… …
23Correlation and dependence — This article is about correlation and dependence in statistical data. For other uses, see correlation (disambiguation). In statistics, dependence refers to any statistical relationship between two random variables or two sets of data. Correlation …
24Maximum likelihood — In statistics, maximum likelihood estimation (MLE) is a method of estimating the parameters of a statistical model. When applied to a data set and given a statistical model, maximum likelihood estimation provides estimates for the model s… …
25Productivity — in economics refers to measures of output from production processes, per unit of input. Labor productivity, for example, is typically measured as a ratio of output per labor hour, an input. Productivity may be conceived of as a measure of the… …
26Errors and residuals in statistics — For other senses of the word residual , see Residual. In statistics and optimization, statistical errors and residuals are two closely related and easily confused measures of the deviation of a sample from its theoretical value . The error of a… …
27Computer-adaptive testing — A computer adaptive testing (CAT) is a method for administering tests that adapts to the examinee s ability level. For this reason, it has also been called tailored testing . How CAT worksCAT successively selects questions so as to maximize the… …
28Regression dilution — is a statistical phenomenon also known as attenuation . Consider fitting a straight line for the relationship of an outcome variable y to a predictor variable x, and estimating the gradient (slope) of the line. Statistical variability,… …
29Covariance — This article is about the measure of linear relation between random variables. For other uses, see Covariance (disambiguation). In probability theory and statistics, covariance is a measure of how much two variables change together. Variance is a …
30Mean difference — The mean difference is a measure of statistical dispersion equal to the average absolute difference of two independent values drawn from a probability distribution. A related statistic is the relative mean difference, which is the mean difference …
