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The SURVEYMEANS Procedure |

If your design has multiple stages of selection and you are specifying the RATE= option, you should input the first-stage sampling rate, which is the ratio of the number of PSUs in the sample to the total number of PSUs in the study population. If you are specifying the TOTAL= option for a multistage design, you should input the total number of PSUs in the study population. See the section "Primary Sampling Units (PSUs)" for more details.

For a nonstratified sample design, or for a stratified
sample design with the same sampling rate or the same
population total in all strata, you should use the
RATE=*value* option or the TOTAL=*value*
option. If your sample design is stratified with
different sampling rates or population totals in the
strata, then you can use the RATE=*
SAS-data-set* option or the TOTAL=*
SAS-data-set* option to name a SAS data set that
contains the stratum sampling rates or totals. This
data set is called a *secondary data set*, as
opposed to the *primary data set* that you specify
with the DATA= option.

The secondary data set must contain all the
stratification variables listed in the STRATA statement
and all the variables in the BY statement. If there are
formats associated with the STRATA variables and the BY
variables, then the formats must be consistent in the
primary and the secondary data sets. If you specify the
TOTAL=*SAS-data-set* option, the secondary
data set must have a variable named _TOTAL_ that
contains the stratum population totals. Or if you
specify the RATE=*SAS-data-set* option, the
secondary data set must have a variable named
_RATE_ that contains the stratum sampling rates. The
secondary data set must contain all BY and STRATA groups
that occur in the primary data set. If the secondary
data set contains more than one observation for any one
stratum, then the procedure uses the first value of
_TOTAL_ or _RATE_ for that stratum and
ignores the rest.

The *value* in the RATE= option or the values
of _RATE_ in the secondary data set must be
positive numbers. You can specify *value* as a
number between 0 and 1. Or you can specify *
value* in percentage form as a number between 1 and 100,
and PROC SURVEYMEANS will convert that number to a
proportion. The procedure treats the value 1 as 100%,
and not the percentage form 1%.

If you specify the TOTAL=*value* option,
*value* must not be less than the sample size.
If you provide stratum population totals in a secondary
data set, these values must not be less than the
corresponding stratum sample sizes.

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