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Please help with one problem

8 messages · Sarah Goslee, Jeff Newmiller, diavolo_vam +2 more

Original
diavolo_vam
# 
It is interesting to graph the distribution of the standardized average as n
increases. Do this when the Xi are
uniform on [0; 1]. Look at the histogram when n is 1, 5, 10 and 25. Do you
see the normal curve taking shape?
(A rule of thumb is that if the Xi are not too skewed, then n > 25 should
make the average approximately
normal. You might want
mu=(b+a)/2
sigma=(b-a)/sqrt(12)
(mean(runif(n,a,b))-mu)/(sigma/sqrt(n))
}
where the formulas for the mean and standard deviation are given. )


Thank you very much!
Sarah Goslee
# 
My first instinct is to suggest that you ask your professor or TA for
help, since this looks remarkably like a homework problem. We are
not here to do your work for you.

Failing that, what have you tried? Have you gotten error messages or
otherwise gone wrong? We will help with specific R questions presented
with complete information as described in the posting guide. This isn't
an R question.

Sarah
On Thu, Dec 16, 2010 at 1:12 PM, diavolo_vam <venci9n at abv.bg> wrote:

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      diavolo_vam
    

    

      
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Hello Sarah, 
Thank you for your post, but this is one task from simpleR book, and I want
to understand the lesson. If you don`t want to help me, OK no problem, but
if anyone can help let do it.

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      Jeff Newmiller
    

    

      
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Whether you selected the problem or a teacher did, you need to stay on topic and provide specific examples of code you have tried with sample input data as needed to make the code self-contained.
Ask about R, not basic statistics.

        
"diavolo_vam" <venci9n at abv.bg> wrote:

        

            

      
      
      
    

        

      
      
    

        
---------------------------------------------------------------------------
Jeff Newmiller                        The     .....       .....  Go Live...
DCN:<jdnewmil at dcn.davis.ca.us>        Basics: ##.#.       ##.#.  Live Go...
                                      Live:   OO#.. Dead: OO#..  Playing
Research Engineer (Solar/Batteries            O.O#.       #.O#.  with
/Software/Embedded Controllers)               .OO#.       .OO#.  rocks...1k
---------------------------------------------------------------------------
Sent from my phone. Please excuse my brevity.

  
  


  


      

    

    

      
      

        


  

        

      Sarah Goslee
    

    

      
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Please see the second half of my original reply, reprinted here for
your convenience:

Failing that, what have you tried? Have you gotten error messages or
otherwise gone wrong? We will help with specific R questions presented
with complete information as described in the posting guide. This isn't
an R question.

In other words, what's your question?

Sarah

        
On Thu, Dec 16, 2010 at 1:59 PM, diavolo_vam <venci9n at abv.bg> wrote:

            

      
      
      
    

  
    

      
      
    

  


  


      

    

    

      
      

        
      

    

    

      
      

        


  

        

      Jannis
    

    

      
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Hi,

I would suggest two things:

1. Use a subject related to your problem when posting to the list!
2. State a question (as Sarah has already said)!

Like this nobody can really understand what you want (or at least I cant!).

Jannis


diavolo_vam schrieb:

            

      
      
      
    

  
  


  


      

    

    

      
      

        


  

        

      Greg Snow
    

    

      
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The clt.examp function in the TeachingDemos package shows the effect of sample size on approximate normality for 4 different distribution of which the uniform distribution is one.  This may do what you want, or you could start with that code and modify it to do what you want.

If not then try better explaining what you want or what your actual question is.