[R] difference in results from R vs SPSS
fiona.sammut at um.edu.mt
Sat Jun 24 13:51:36 CEST 2006
Thanks for the reply. The mistake in 1 resulted to be due to using a
different number of decimal places in the data.
As regards 2, will check it out again.
> Fiona Sammut wrote:
>> Hi all,
>> 1. I am doing some data analysis using both R and SPSS, to get used
>> to both software packages. I had performed linear regression in R
>> and SPSS for a number of times before this last one and the resulting
>> coefficient values always matched. However, this last data set I was
>> analyzing using simple linear regression and using the command
>> lm(y~x), gave me different readings from R and SPSS:
>> R: y= 33.803 + 6.897x
>> SPSS: y= 47.589 + 6.263x
>> I have no doubts regarding the procedure employed in SPSS and I am
>> sure I am using the same dataset for both software packages.
> My guess is you have missing values defined in SPSS but don't have
> those same values set to NA in R. Have you requested basic
> descriptive statistics in both programs and found that they match?
> Also, perhaps x a factor in R. If so, how are its contrasts set?
>> 2. Correct me if I am wrong, but from what I've read, it seems that
>> the command /anova /in R works out an analysis of variance without
>> including the intercept. Is that so? Cause again I am working out
>> an anova in R and SPSS and I got different resulting sums of squares
>> and different degrees of freedom. I thought this was because one
>> package is working with an intercept and the other isn't.
> I don't think this has anything to do with the discrepancy.
>> Can anyone enlighten me as to what might have happened in both 1. and
>> 2. please? Are they both due to my poor knowledge of R or could
>> occurences as above happen?
>> 3. I would like a reference to a command which can be used to fit a
>> distribution to a disrete distribution.
>> Thanks in advance for your consideration.
>> - Fiona Sammut
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