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svymean.hlp
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1998-11-22
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.-
help for ^svymean^, ^svytotal^, ^svyratio^, ^svyprop^ (manual: ^[R] svymean^)
.-
Estimate means, totals, ratios, and proportions for survey data
---------------------------------------------------------------
^svymean^ varlist [weight] [^if^ exp] [^in^ range] [^,^ common_options]
^svytotal^ varlist [weight] [^if^ exp] [^in^ range] [^,^ common_options]
^svyratio^ varname [^/^] varname [varname [^/^] varname ...]
[weight] [^if^ exp] [^in^ range] [^,^ common_options]
^svyprop^ varlist [weight] [^if^ exp] [^in^ range] [^,^ svyprop_options]
where common_options are
^str^ata^(^varname^) psu(^varname^) fpc(^varname^) by(^varlist^)^
{^com^plete|^av^ailable} ^sub^pop(varname) ^srs^subpop ^nolab^el
^l^evel^(^#^) ci deff deft meff meft obs size^
and svyprop_options are
^str^ata^(^varname^) psu(^varname^) fpc(^varname^) by(^varlist^)^
^sub^pop^(^varname^) nolab^el ^for^mat^(%^fmt^)^
^svymean^, ^svyratio^, and ^svytotal^ typed without arguments redisplay previous
results. Any of the following options can be used when redisplaying results:
^l^evel^(^#^) ci deff deft meff meft obs size^
All of these commands allow ^pweight^s and ^iweight^s; see help @weights@.
Warning: Use of ^if^ or ^in^ restrictions will not produce correct variance
estimates for subpopulations in many cases. To compare estimates
for subpopulations, use the ^by()^ or ^subpop()^ options.
Description
-----------
^svymean^, ^svytotal^, ^svyratio^, and ^svyprop^ produce estimates of
finite-population means, totals, ratios, and proportions. Associated variance
estimates, design effects (deff and deft), and misspecification effects (meff
and meft) are also computed.
Estimates for multiple subpopulations can be obtained using the ^by()^ option.
The ^subpop()^ option will give estimates for a single population.
For linear regression, logistic regression, and probit estimation with survey
data, see help @svyreg@.
To describe the strata and PSUs of your data and to handle the error message
"stratum with only one PSU detected", see help @svydes@.
To estimate differences (and other linear combinations) of means, totals, and
ratios, see help @svylc@. To perform hypothesis tests, see help @svytest@.
Options
-------
^strata()^, ^psu()^, and ^fpc()^ are described in ^svyset^; see help @svyset@.
^by(^varlist^)^ specifies that estimates be computed for the subpopulations
defined by different values of the variable(s) in the varlist.
^subpop(^varname^)^ specifies that estimates be computed for the single
subpopulation defined by the observations for which varname~=0.
Typically, varname=1 defines the subpopulation and varname=0 indicates
observations not belonging to the subpopulation. For observations whose
subpopulation status is uncertain, varname should be set to missing.
^srssubpop^ can only be specified if ^by()^ or ^subpop()^ is specified. ^srssubpop^
requests that deff and deft be computed using an estimate of simple-
random-sampling variance for sampling within a subpopulation. If
^srssubpop^ is not specified, deff and deft are computed using an estimate
of simple-random-sampling variance for sampling from the entire
population. Typically, ^srssubpop^ would be given when computing
subpopulation estimates by strata or by groups of strata.
^nolabel^ can only be specified when ^by()^ is specified. ^nolabel^ requests that
numeric values rather than value labels be used to label output for
subpopulations. By default, value labels are used.
{^complete^|^available^} specifies how missing values are to be handled. ^complete^
specifies that only observations with complete data should be used.
^available^ specifies that all available nonmissing values be used for each
estimate.
If neither ^complete^ nor ^available^ is specified, ^available^ is the default
when there are missing values and there are two or more variables in the
varlist (or four or more for ^svyratio^). ^complete^ must be specified to
compute the covariance or to use ^svytest^ or ^svylc^ after running the
command; see help @svytest@ and help @svylc@.
^format(%^fmt^)^ (^svyprop^ only) specifies the display format for the proportion
estimates and their standard errors. The default is ^%9.6f^.
^level(^#^)^ specifies the confidence level (i.e., nominal coverage rate), in
percent, for confidence intervals; see help @level@.
^ci^ requests that confidence intervals be displayed. If no display options are
specified then, by default, confidence intervals are displayed.
^deff^ requests that the design-effect measure deff be displayed. If no display
options are specified then, by default, deff is displayed.
^deft^ requests that the design-effect measure deft be displayed. See
^[R] svymean^ for a discussion on deff and deft.
^meff^ requests that the meff measure of misspecification effects be displayed.
^meft^ requests that the meft measure of misspecification effects be displayed.
See ^[R] svymean^ for a discussion of meff and meft.
^obs^ requests that the number of observations used for the computation of the
estimate be displayed for each row of estimates.
^size^ requests that the estimate of the (sub)population size be displayed for
each row of estimates. The (sub)population size estimate equals the sum
of the weights for those observations used for the mean/total/ratio
estimate.
Examples
--------
. ^svyset strata stratan^
. ^svyset pweight finwgt^
. ^svymean birthwgt^
. ^svymean birthwgt, by(race)^
. ^svymean birthwgt, subpop(race)^
. ^svyset strata strata^
. ^svyset psu psu^
. ^svyset pweight finalwgt^
. ^svymean tcresult tgresult^
. ^svytotal heartatk, by(sex)^
. ^svyratio hdresult/tcresult^
. ^svyprop race agegrp^
Also see
--------
Manual: ^[U] 36 Overview of survey estimation^
^[R] svymean^
On-line: help for @ci@, @svy@, @svydes@, @svylc@, @svyreg@, @svyset@, @svytest@