User Guide

Chapter
14
Descriptive
s
The Descriptives procedure displays univariate summary statistics for several
variables in a single table and calculates standardized values (z scores). Variables
can be ordered by the size of their means (in ascending or descending order),
alphabetically, or by the order in which you select the variables (the default).
When z scores are saved, they are added to the data in the Data Editor and are
available for charts, data listings, and analyses. When variables are recorded in
different units (for example, gross domestic product per capita and percentage
literate), a z-score transformation places variables on a common scale for easier
visual comparison.
Example. If each case in your data contains the daily sales totals for each member
of the sales staff (for example, one entry for Bob, one for Kim, one for Brian, etc.)
collected each day for several months, the Descriptives procedure can compute
the average daily sales for each staff member and order the results from highest
average sales to lowest.
Statistics. Sample size, mean, minimum, maximum, standard deviation, variance,
range, sum, standard error of the mean, and kurtosis and skewness with their standard
errors.
Data. Use numeric variables after you have screened them graphically for recording
errors, outliers, and distributional anomalies. The Descriptives procedure is very
efficient for large files (thousands of cases).
Assumptions. Most of the available statistics (including z scores) are based on
normal theory and are appropriate for quantitative variables (interval- or ratio-level
measurements) with symmetric distributions (avoid variables with unordered
categories or skewed distributions). The distribution of z scores has the same shape as
that of the original data; therefore, calculating z scores is not a remedy for problem
data.
315