Unbiased estimator
When the sampling distribution of a statistic has a mean equal to the parameter
being estimated.


Unbiased samples
Samples obtained from sample designs in which there is no bias and all
sampling error comes from random sources.


UNICODE
See: Double Byte


Unidimensional scaling
Procedures designed to measure only one attribute of a respondent or object.


Union
The event containing all simple events for both event A and event B. The
concept of union can be extended to more than two events.


Unipolar
An ordinal scale with one positive end and one negative end.


Unit of analysis
The basic element on which the experiment or study is conducted or from
which data are collected. Also known as the respondent, participant, unit,
subject or experimental unit.


Univariate data set
A data set in which one measurement (variable) has been made on each
respondent.


Universe
The set of all the units from which a sample is drawn. Also called the
population.


Unstructured observation
A study in which the observer simply makes notes on the behaviour being
observed.


Unstructured segmentation
Process of segmenting a market using data and analysis when no prior ideas
are held about the number of segments, what they are, or how and why they
are different.


Urban population
As defined by the 1980 census, all persons living in urbanized areas and in
places of 2,500 or more inhabitants outside urbanized areas.


Urbanized areas
A central city or cities and the surrounding (contiguous) closely settled
territory. Must have at least 50,000 inhabitants.