[R] extracting pvalues from ttest

[1Rnwb]

Hello, I am using "B" as a vector to store all the t.tests. since i am a
newbie to both R and statistics I am not sure if "B" is the list. Also I see
"c" used in the do.call formula and do not know what it is being used for. I
used aggregate but getting this error" Error in aggregate.data.frame(eo,
eo$PlateID, function(.sub) t.test(ENA78 ~  :   'by' must be a list". 
As i mention in my OP that I am using is function from an earlier post.
any help is appreciated.
Thanks
Sharad


Jun Shen-3 wrote:
> 
> I never used "by". Is "B" a list? If not, I am not sure if lapply can take
> it. Try aggregate().
> 
> On Fri, Aug 28, 2009 at 10:53 AM, 1Rnwb <sbpurohit at gmail.com> wrote:
> 
>>
>> Hello list,
>>
>> I have a similar issue as this post
>> http://tolstoy.newcastle.edu.au/R/e6/help/09/04/11438.html#options2 and I
>> used the suggestion provided by Jorge with modifications to my data
>> do.call(c,lapply(your_list_with_the_t_tests,function(x) x$p.value))
>>
>> but I am getting the following error after excuting the code
>>
>> B<-by(eo,eo$PlateID, function(.sub) t.test(mcp1~Self_T1D,data=.sub,
>> na.rm=T)) #ttest platewise
>> do.call(c,lapply(B, function(x) x$p.value))
>> Error in do.call(c, lapply(B, function(x) x$p.value)) :
>>  'what' must be a character string or a function
>>
>> here "B" is equal to "your_list_with_the_t_tests. is something i am doing
>> wrong
>> >
>> --
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>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 
> 

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