The SURVEYFREQ Procedure
Coefficient of Variation
If you specify the CV option in the TABLES statement, PROC SURVEYFREQ computes the coefficients of variation for the proportion estimates in the frequency and crosstabulation tables. The coefficient of variation is the ratio of the standard error to the estimate.
For the proportion in table cell (r, c), the coefficient of variation is computed as
![\[ \mr {CV}(\widehat{P}_{rc}) = \mr {StdErr}(\widehat{P}_{rc}) ~ / ~ \widehat{P}_{rc} \]](images/statug_surveyfreq0161.png){kind=small} |
where 
is the estimate of the proportion in table cell (r, c), and 
is the standard error of the estimate. The coefficients of variation for row proportions and column proportions are computed
similarly.
If you specify the CVWT option in the TABLES statement, PROC SURVEYFREQ computes the coefficients of variation for the weighted frequencies (estimated totals) in the crosstabulation tables. For the total in table cell (r, c), the coefficient of variation is computed as
![\[ \mr {CV}(\widehat{N}_{rc}) = \mr {StdErr}(\widehat{N}_{rc}) ~ / ~ \widehat{N}_{rc} \]](images/statug_surveyfreq0162.png){kind=small} |
where 
is the estimate of the total in table cell (r, c), and 
is the standard error of the estimate. The coefficients of variation for row totals, column totals, and the overall total
are computed similarly.