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Re: st: regression using generalized linear model
From
Nick Cox <[email protected]>
To
"[email protected]" <[email protected]>
Subject
Re: st: regression using generalized linear model
Date
Tue, 11 Mar 2014 19:18:23 +0000
Some confusion here. That's absolutely no rule that dependent
variables must be integer in analysis of variance. Almost all
applications would be void otherwise!
Perhaps this is a slip -- you really mean _independent_ variables --
but it is also untrue that predictors in analysis of variance must be
integers.
I've already quietly pointed out to you that "Stata" is the correct
spelling. Learning the correct spelling is actually in your best
interests: if you wrote "STATA" in a paper or a presentation some
fraction of your audience would think "he can't even spell the program
name correctly!". They would almost certainly not be blunt like me and
point it out, but it's part of my self-assigned job here to teach you!
Nick
[email protected]
On 11 March 2014 19:06, Trung (Aidan) Nguyen <[email protected]> wrote:
> Thanks Joe and Nick,
>
> I used the encode command to turn the class variable 'a' into a
> numeric value. However, for anova command to work, all the dependent
> variables must be of integer value. If I assigned integer values for
> all the dependent variables, then it would not lead me to the same
> results I get from the GLM command in SAS. Yes, I did use the # for
> the interaction effects in my STATA code. Would you suggest the glm
> command in STATA?
>
> x is the dependent var
> a and b are the classification effects
>
> Thanks.
>
>
>
> On Tue, Mar 11, 2014 at 12:51 PM, Joe Canner <[email protected]> wrote:
>>
>> Actually, Aidan provides us with most of the answer in his post. He indicates that variable -a- is a "string character" and that -u- "contains non integer and negative values".
>>
>> Nick has suggested a fix for string variables (-encode-). -destring- may also work. I don't remember enough about PROC GLM to know how u*u should be translated into Stata. If the asterisk is an interaction, perhaps a hash(#) would work better in Stata.
>>
>> Incidentally, how did Aidan get the asterisks to work at all in Stata? Is that new in version 13?
>>
>> Joe
>>
>> -----Original Message-----
>> From: [email protected] [mailto:[email protected]] On Behalf Of Nick Cox
>> Sent: Tuesday, March 11, 2014 2:40 PM
>> To: [email protected]
>> Subject: Re: st: regression using generalized linear model
>>
>> I've never used SAS but I have used Stata [NB].
>>
>> But the message does explain the problem, which may be why no-one
>> answered this first time this was asked.
>>
>> At least one of your variables -v y u t a b- contains something other
>> than integers. So,
>>
>> . codebook v y u t a b
>>
>> to see which variable(s) don't come up to scratch. Perhaps one is
>> string. Even if SAS permits string predictors (I don't know its
>> terminology), Stata expects you to -encode- string variables before
>> using them in -anova-.
>>
>> (Please note our policy on repeating posts. It's best to wonder why a
>> post didn't get answered, and revise it, and not to seem too
>> impatient.)
>>
>> Nick
>> [email protected]
>>
>> On 11 March 2014 18:28, Aidan Trung Nguyen <[email protected]> wrote:
>>
>> > I'm trying to write the STATA equivalent of the followingSAS statement:
>> >
>> > proc glm data=datasetclass a b model x = v*y*y u*u t a*b
>> > weight w
>> > output out = outputdataset
>> >
>> >
>> > a is a string character
>> > b, x, v, y, u, t are numeric
>> > u contains non integer and negative values
>> >
>> > I tried the below command but without success:anova x v*y*y u*u t a*b
>> >
>> > error message : factor variables may not contain non integervalues Any guidance is much appreciated.
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