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Glossary Term
A measure of the range of values in a set of numbers. Standard deviation is a statistic used as a measure of the dispersion or variation in a distribution, equal to the square root of the arithmetic mean of the squares of the deviations from the arithmetic mean.
Glossary Term
The standard deviations of the sample in a frequency distribution, obtained by dividing the standard deviation by the square root of the total number of cases in the frequency distribution.
Glossary Term
A method for converting an individual score into a standard form. While similar to a z-score, t-score is used when the conversion is made without knowledge of the population standard deviation and mean.
Glossary Term
An alteration or difference from a norm or standard.
Glossary Term
A method for converting an individual score into a standard form. The z-score indicates how far and in what direction an item deviates from its distribution's mean, expressed in units of standard deviation. Calculation of a z-score requires knowledge about the population's standard deviation and mean.
