Information Technology Reference
In-Depth Information
Glossary, Grouped
by Related but
Distinct Terms
ACCURACY AND PRECISION
An
accurate
estimate is close to the estimated quantity. A
precise
interval
estimate is a narrow one. Precise measurements made with a dozen or
more decimal places may still not be accurate.
DETERMINISTIC AND STOCHASTIC
A phenomenon is
deterministic
when its outcome is inevitable and all
observations will take specific value.
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A phenomenon is
stochastic
when its
outcome may take different values in accordance with some probability
distribution.
DICHOTOMOUS, CATEGORICAL, ORDINAL,
METRIC DATA
Dichotomous
data have two values and take the form “yes or no,” “got
better or got worse.”
Categorical
data have two or more categories such as yes, no, and unde-
cided. Categorical data may be ordered (opposed, indifferent, in favor) or
unordered (dichotomous, categorical, ordinal, metric).
Preferences can be placed on an ordered or
ordinal
scale such as
strongly opposed, opposed, indifferent, in favor, strongly in favor.
Metric
data can be placed on a scale that permits meaningful subtrac-
tion; for example, while “in favor” minus “indifferent” may not be mean-
ingful, 35.6 pounds minus 30.2 pounds is.
Metric data can be grouped so as to evaluate them by statistical
methods applicable to categorical or ordinal data. But to do so would be
1
These observations may be subject to measurement error.
