Download SPSS® Base 13.0 User's Guide

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342
Chapter 17
are longer than those of a normal distribution; a negative value for kurtosis indicates
shorter tails (becoming like those of a box-shaped uniform distribution).
Standard Error of Skewness. The ratio of skewness to its standard error can be used
as a test of normality (that is, you can reject normality if the ratio is less than -2 or
greater than +2). A large positive value for skewness indicates a long right tail; an
extreme negative value, a long left tail.
Sum. The sum or total of the values, across all cases with nonmissing values.
Variance. A measure of dispersion around the mean, equal to the sum of squared
deviations from the mean divided by one less than the number of cases. The variance
is measured in units that are the square of those of the variable itself.