[R] chi-Squared distribution in Friedman test

[Prasanna Balaprakash]

Dear R helpers:


Thanks for the previous reply. I am using Friedman racing test. According the the book "Pratical Nonprametric Statistic" by WJ Conover, after computing the statistics, he suggested to use chi-squared or F distribution to accept or reject null hypothesis. After looking into the source code, I found that R uses chi-sqaured distribution as below:

PVAL <- pchisq(STATISTIC, PARAMETER, lower = FALSE)

but still I cant figure out why they are using this pschisq insted of dchisq. Sorry I am wrong!!


Thanking you
truly
Prasanna









>
>----- Original Message ----- 
>From: "Dimitris Rizopoulos" <dimitris.rizopoulos at med.kuleuven.ac.be>
>To: "Prasanna Balaprakash" <pbalapra at ulb.ac.be>
>Cc: <r-help at stat.math.ethz.ch>
>Sent: Friday, January 21, 2005 1:05 PM
>Subject: Re: [R] chi-Squared distribution
>
>
>> if you check ?qchisq, you'll see that the second
>
>My mistake, the third argument
>
>> argument of the function denotes the non-centrality parameter! Try
>>
>> qchisq(0.75, 1:3)
>>
>> to get your answer.
>>
>> Best,
>> Dimitris
>>
>> ----
>> Dimitris Rizopoulos
>> Ph.D. Student
>> Biostatistical Centre
>> School of Public Health
>> Catholic University of Leuven
>>
>> Address: Kapucijnenvoer 35, Leuven, Belgium
>> Tel: +32/16/336899
>> Fax: +32/16/337015
>> Web: http://www.med.kuleuven.ac.be/biostat
>>     http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm
>>
>>
>> ----- Original Message ----- 
>> From: "Prasanna Balaprakash" <pbalapra at ulb.ac.be>
>> To: <r-help at stat.math.ethz.ch>
>> Sent: Friday, January 21, 2005 12:27 PM
>> Subject: [R] chi-Squared distribution
>>
>>
>>> Dear Rs:
>>>
>>>
>>> outer(1:3, 1:3, function(df1, df2) qf(0.95, df1, df2))
>>>
>>> I compare this F distribution results with the table, the answers 
>>> were perfect. But I need to see for chi-sqaured distribution. When 
>>> I employed the similar formula
>>>
>>> outer(1:3, 1:3, function(df1, df2) qchisq(0.95, df1, df2)) , I am 
>>> getting unexpected results. I need to see the following values:
>>>
>>>     p=0.750  .....
>>> 1     1.323
>>>
>>> 2     2.773
>>>
>>> 3     4.108
>>>
>>>
>>> Thanking you
>>> Prasanna
>>>
>>>
>>>
>>>
>>>
>>>
>>> Prasanna Balaprakash,
>>> Université Libre de Bruxelles,
>>> 50, Av. F. Roosevelt, CP 194/6,
>>> B-1050 Brussels,
>>> Belgium.
>>>
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