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help for destest                                                 John Hendrickx
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destest

        destest [termlist] [using filename] [, joint equal outraw replace
                           ndec(#) sigcut(numlist) sigsym(list) sigsep(#)

Description

destest is a companion program for desmat. It is used after estimating a model
to perform a Wald test on model terms.  The termlist consists of one or more
terms as specified in desmat. A term can consist of a single variable, or two
or more variables separated by either asterisks or periods. If asterisks are
used, they will be changed into periods by destest, i.e. only the highest order
interaction will be tested. If no arguments are specified, all terms from the
last desmat model will be tested.

The default is to test whether the effects of each separate term are equal to
zero. If the option joint is specified, destest will test instead whether all
the effects in all the terms are jointly equal to zero. If the option equal is
specified, destest will test whether the effects of each separate term are
equal. The joint and equal options may be combined to test whether all effects
are jointly equal, although this would be a somewhat peculiar hypothesis. Only
the first letter of the joint and equal option is sigificant.

If using filename is specified then the results are written to a tab- delimited
ascii file. The default extension for filename is .out (cf.  outsheet). If
filename already exists, desrep will attempt to find a valid filename by
appending a number (see outshee2). The replace option can be used to overwrite
an existing file.

Options

The options ndec(), sigcut(), sigsym(), sigsep() have the same usage as in 
desrep.

ndec(#) specifies the number of decimal places. Default=3.

sigcut(numlist) specifies levels of significance to be indicated in the output.
    destest places a symbol next to the Chi-square or F statistics to indicate
    whether these are significant at a certain level.  The sigcut option is
    used to specify these levels of significance.  The numlist should contain a
    list of values in descending order with the same number of elements as the
    string list in sigsym. For example, sigcut(.1 .05 .01 .001) together with
    sigsym(# * ** ***) will use the symbols # for p < .1, * for p < .05, ** for
    p < .01, and *** for p < .001. The default is (.05 .01).

sigsym(list) specifies set of symbols corresponding with the levels of
    significance given by sigcut. Default=(* **).

sigsep(#) spcifies the number of spaces between coefficients and symbols
    indicating significance. Default=0.

The following two options apply only if using has been specified to write the
data to a tab-delimited ascii file:

outraw requests that results be written using their default formats, e.g. %9.0g
    for floats. In addition, a tab will be inserted between coefficients and
    significance symbols. Otherwise, the variables are written with a fixed
    number of decimal places as specified by the ndec option (default 3) and
    significance symbols are appended to coefficients if sigsep=0.
    Default=nooutraw.

replace specifies that any existing output file should be replaced.  If not
    specified, destest appends a number to the filename if it already exists.
    If no valid name has been found after appending 1 to 20, the process stops
    and the output is not saved. Default=noreplace.

Macro variables to control layout

Global macro variables can be used to specify different defaults for these
options, either for the session or for all Stata sessions, by placing the
global variables in the user's profile.do.

$D_NDEC
$D_SIGCUT
$D_SIGSYM
$D_SIGSEP
$D_RAW
$D_REPL

Options specified in the destest command string will override these global
variables.

Notes

desmat creates global macro variables $term1, $term2, etc.  containing a
varlist for each term in the model. destest runs through each of these terms,
finds the terms corresponding with the termlist, and runs testparm with the
varlist corresponding with each term.  If these global variables have not been
defined, destest will only print header information. These global variables can
of course also be used separately in testparm, sw, or related programs.

Aso see

 Manual: [R] Test
On-line: help for desmat, desrep, outsheet, outshee2, showtrms, test