User Guide

Chapter
19
OLAP Cubes
The OLAP (Online Analytical Processing) Cubes procedure calculates totals, means,
and other un
ivariate statistics for continuous summary variables within categories of
one or more categorical grouping variables. A separate layer in the table is created for
each category of each grouping variable.
Example. T
otal and average sales for different regions and product lines within regions.
Statistics. Sum, number of cases, mean, median, grouped median, standard error
of the mean, minimum, maximum, range, variable value of the first category of
the groupi
ng variable, variable value of the last category of the grouping variable,
standard deviation, variance, kurtosis, standard error of kurtosis, skewness, standard
error of skewness, percentage of total cases, percentage of total sum, percentage
of total c
ases within grouping variables, percentage of total sum within grouping
variables, geometric mean, and harmonic mean.
Data. The summary variables are quantitative (continuous variables measured on an
interval
or ratio scale), and the grouping variables are categorical. The values of
categorical variables can be numeric or short string.
Assumptions. Some of the optional subgroup statistics, such as the mean and standard
deviati
on, are based on normal theory and are appropriate for quantitative variables
with symmetric distributions. Robust statistics, such as the median and range, are
appropriate for quantitative variables that may or may not meet the assumption of
normal
ity.
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