[R] Problem in performing goodness of fit test in R.
(Ted Harding)
Ted.Harding at manchester.ac.uk
Sun Feb 14 11:53:39 CET 2010
Good that you got it to work somehow!
Faiz: can you report the result, exactly as returned by R, of
sum(c(1,1,1,1,1,1)/6) - 1
??
On my Linux with R version 2.10.0 (2009-10-26) this gives 0.
(And, by the way, did you really mean to say you were using
"R 2.1.01"? Was this a typing error for "R 2.10.1"?)
Ted.
On 14-Feb-10 09:26:00, Faiz Rasool wrote:
> Hi all,
>
> Following Denis's code, I am able to carry out goodness of fit test.
>
> However the responses I have received, indicate that the code I
> mentioned in
> a prior email was not incorrect. inclusion of rep(1,6)/6 made a
> difference
> for me. I am using windows xp and R 2.1.01. Does difference of
> operating
> system makes a difference? As without rep(1,6)/6 R would not carry out
> chisq.test on my computer. The code I got it to work follows.
>
>> freq=c(22,21,22,27,22,36)#frequencies obtained after rolling the dice
>> 150
>> times.
>> prob=rep(1,6)/6#change made after Dennis's suggestion.
>> chisq.test(freq,p=prob)#no error message received now.
>
> Chi-squared test for given probabilities
>
> data: freq
> X-squared = 6.72, df = 5, p-value = 0.2423
>
> thanks everyone,
> Faiz.
>
> ----- Original Message -----
> From: "Ted Harding" <Ted.Harding at manchester.ac.uk>
> To: <R-help at r-project.org>
> Cc: "Faiz Rasool" <faiz7r at gmail.com>
> Sent: Sunday, February 14, 2010 2:02 PM
> Subject: RE: [R] Problem in performing goodness of fit test in R.
>
>
>> On 14-Feb-10 07:42:12, Faiz Rasool wrote:
>>> I am trying to perform goodness of fit test using R. I am using this
>>> website
>>> http://wiener.math.csi.cuny.edu/Statistics/R/simpleR/stat013.html
>>> for help. However, I am unable to carry out the test successfully. My
>>> code follows. It is taken from the website just mentioned.
>>>
>> freq=c(22,21,22,27,22,36) # frequencies obtained after
>> # rolling the dice 150 times.
>> prob=c(1,1,1,1,1,1)/6 # specify expected frequency for each category.
>> chisq.test(freq,p=prob) # I do not know what this line means.
>> # I just followed instructions on the
>> # website.
>>>
>>> The erorr I receive is "erorr in chisq.test(freq,p=prob)/6
>>> probabilities must sum to 1"
>>>
>>> I am very new to R, so any help would be appreciated.
>>> Faiz.
>>
>> I suspect that you must have made an error in entering the commands
>> into R. Prime suspect: You did not have 6 1's in p -- for example
>> you may have put
>>
>> prob=c(1,1,1,1,1)/6
>>
>> (with only five). I copied your code (as trivially reformatted above)
>> straight into R using copy&paste with the mouse, with results:
>>
>> freq=c(22,21,22,27,22,36) # frequencies obtained after
>> # rolling the dice 150 times.
>> prob=c(1,1,1,1,1,1)/6 # specify expected frequency for each category.
>> chisq.test(freq,p=prob) # I do not know what this line means.
>>
>> # Chi-squared test for given probabilities
>> # data: freq
>> # X-squared = 6.72, df = 5, p-value = 0.2423
>> # I just followed instructions on the
>> # website.
>>
>> So it worked as it should work. Therefore something went wrong
>> when you entered the code. Check your input!
>>
>> Hoping this helps,
>> Ted.
>>
>> --------------------------------------------------------------------
>> E-Mail: (Ted Harding) <Ted.Harding at manchester.ac.uk>
>> Fax-to-email: +44 (0)870 094 0861
>> Date: 14-Feb-10 Time: 09:02:01
>> ------------------------------ XFMail ------------------------------
>
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E-Mail: (Ted Harding) <Ted.Harding at manchester.ac.uk>
Fax-to-email: +44 (0)870 094 0861
Date: 14-Feb-10 Time: 10:53:34
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