Thanks for the plug, Al.
Interestingly, StataCorp (relatively recently) implemented lots of
non-central distribution functions... but not for the t, the one
likely needed most frequently!
While you can get the two-sided noncentral t p-values from Stata's
noncentral F (square the t' and the noncentrality parameter), the
one-sided values are not available.
This seems like a clear oversight to me.
Beyond that, though, the nct package (hopefully) makes it simple
to get whichever missing parameter you want.
Tom
-----------------------------------
Thomas J. Steichen
[email protected]
-----------------------------------
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Feiveson, Alan H. (JSC-SK311)
Sent: Friday, December 14, 2007 10:23 AM
To: [email protected]
Subject: st: RE: RE: [programming] syntax syntax
Thanks very much Tom - Your clear explanations resolve several hours of
frustration. By the way, this program (if it ever runs) makes use of
your non-central t package. So I'll use this opportunity to put in a
plug for it.
(ssc describe nct)
Al
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Steichen,
Thomas J.
Sent: Friday, December 14, 2007 9:11 AM
To: '[email protected]'
Subject: st: RE: [programming] syntax syntax
Al,
When you specify an optional option as a real in the syntax statement,
you must also specify the default value.
For varlist, you can use suboption (default=none) to keep it blank.
Then your planned approach will work. For example:
syntax [varlist(default=none)] [if] [in] , confdir(string) ///
level(real) [ xb1(real 1.0) n1(string) ]
Tom
-----------------------------------
Thomas J. Steichen
[email protected]
-----------------------------------
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Feiveson,
Alan H. (JSC-SK311)
Sent: Friday, December 14, 2007 9:58 AM
To: [email protected]
Subject: st: [programming] syntax syntax
Hi - I have two questions regarding the syntax of the "syntax"
statement:
1)
I've been trying to write a program (effcon.ado) that starts with
syntax [varlist] [if] [in] , confdir(string) level(real) [xb1(string)
n1(string) ]
tokenize `varlist'
local nv: word count `varlist'
di " nv = `nv'"
For some reason, this will work only if the "xb1" option is a string,
but not if I change it to real:
a) output when xb1 is a string in the syntax statement:
.. discard
.. effcon x1,level(.95) confdir(L) xb1(xyz) n1(asd) nv = 1 [it works,
etc.]
But if I change the "xb1" option to real, I get a syntax error:
b) output when xb1 is real in the syntax statement:
.. set trace on
.. discard
.. effcon x1,level(.95) confdir(L) xb1(1.234) n1(asd)
------------------------------------------------------------------------
-------------- begin effcon ---
- version 9.0
- syntax [varlist] [if] [in] , confdir(string) level(real) [xb1(real)
n1(string) ]
invalid syntax
------------------------------------------------------------------------
---------------- end effcon ---
r(197);
2)
My second question deals with the word count of `varlist'. I want to
have the option of no variables in varlist. But if I don't list any in
my calling statement, `'varlist' is treated as a list of all the
variables in my dataset. I thought I could just count the elements in
`'varlist' and then do something if that count is zero (i.e. if I don't
enter any variables) - but the count comes out 12 (in this case) because
I have 12 variables in my data set. Any other suggestions on how to test
if I entered any variables in my calling statement?
Thanks
Al Feiveson
2) Example where I enter no variables but `varlist' contains all my
variables:
Contains data from temprat.dta
obs: 100
vars: 12 13 Dec 2007 08:05
size: 5,200 (99.9% of memory free)
------------------------------------------------------------------------
-------
storage display value
variable name type format label variable label
------------------------------------------------------------------------
-------
R float %9.0g
C float %9.0g
xb1 float %9.0g
xb2 float %9.0g
s float %9.0g
rat float %9.0g
rat10 float %9.0g
a float %9.0g
b float %9.0g
n1 float %9.0g
x1 float %9.0g
x2 float %9.0g
------------------------------------------------------------------------
-------
.. discard
.. set trace on
.. effcon ,level(.95) confdir(L)
------------------------------------------------------------------------
-------------- begin effcon ---
- version 9.0
- syntax [varlist] [if] [in] , confdir(string) level(real) [xb1(string)
n1(string) ]
- tokenize `varlist'
= tokenize R C xb1 xb2 s rat rat10 a b n1 x1 x2
- local nv: word count `varlist'
= local nv: word count R C xb1 xb2 s rat rat10 a b n1 x1 x2
- di " nv = `nv'"
= di " nv = 12"
nv = 12
[rest omitted]
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