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***ALERT NOTE***
SAS Note: SN-002698
Product: STAT
Component: SURVEYMEANS
Title:
Incorrect results when categorical level does not appear in all strata
Keywords:
INCORRSTAT INCORROUT STRATA STRATUM CLASS CHARACTER CATEGORICAL LEVEL
MISSING EXIST
In the SURVEYMEANS procedure, when a STRATA statement is specified and a
categorical (CLASS or character) variable is analyzed, if a level of
the categorical variable does not appear in one or more strata, then the
variance estimation and related statistics for the strata with the
missing level will be incorrect. The incorrect results for this level
include the standard error and variance of the mean, the standard
deviation and variance of the sum, the confidence limits for the mean
and sum, the t statistic and its p-value, and the coefficient of
variation.
To identify categorical variable levels that do not appear in all
strata, specify the LIST option on the STRATA statement and observe the
occurrences of N=0 in the Stratum Information table.
To circumvent this problem, for each instance of N=0 for a categorical
level of interest, issue a separate run of PROC SURVEYMEANS omitting the
empty strata with a WHERE clause.
Reported Releases:
+------------REPORTED------------+ +------FIXED-----+
System Version Level Version Level
AIX/R 7 B1 8.2 2M0
CMS 7 B1 8.2 2M0
DigitUnx 7 B1 8.2 2M0
HP800 7 B1 8.2 2M0
IABI 8 D1 8.2 2M0
MIPS ABI 8 D1 8.2 2M0
MVS 7 B1 8.2 2M0
OS/2 7 B1 8.2 2M0
Solaris 7 B1 8.2 2M0
VMS 7 B1 8.2 2M0
VMS/AXP 7 B1 8.2 2M0
WIN/NT 7 B1 8.2 2M0
Win2000 8 M0 8.2 2M0
Win95 7 B1 8.2 2M0
Win98 7 P1 8.2 2M0
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