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The REG Procedure |
Construction of Q-Q and P-P Plots |
If a normal probability-probability or quantile-quantile plot for the variable is requested, the
nonmissing values of
are first ordered from smallest to largest:
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If a Q-Q plot is requested (with a PLOT statement of the form PLOT yvariableNQQ.), the
th-ordered value
is represented by a point with y-coordinate
and x-coordinate
, where
is the standard normal distribution.
If a P-P plot is requested (with a PLOT statement of the form PLOT yvariableNPP.), the
th-ordered value
is represented by a point with y-coordinate
and x-coordinate
, where
is the mean of the nonmissing
-values and
is the standard deviation. If an
-value has multiplicity
(that is,
), then only the point
is displayed.
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Copyright © 2009 by SAS Institute Inc., Cary, NC, USA. All rights reserved.