SAS Note 002698

Date: Mon Aug 21 2000 - 13:30:41 EDT

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                                      ***ALERT NOTE***
     SAS Note: SN-002698
     Product: STAT
     Component: SURVEYMEANS


    Incorrect results when categorical level does not appear in all strata


    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

    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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