Re: weighted average method for rates

["David L Lorenz" <lorenz@usgs.gov>]

Duo wan,
  The hmisc library has function for computing weighted statistics.  They
all begin with wtd.
Dave


                                                                                
                                                  
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                      s-news-owner@lists.biosta        Subject:  [S] weighted 
average method for rates                            
                      t.wustl.edu                                               
                                                  
                                                                                
                                                  
                                                                                
                                                  
                      11/15/2004 11:43 AM                                       
                                                  
                                                                                
                                                  
                                                                                
                                                  




Dear S-users:


I am trying to combine the rates using common weighted average methods. is
anyone who knows how to use S to do it or assist me with formulaes?


thanks!!!


duowan


num_im=num of improved patients;


num_pat=number of patients.


rate=num_im/num_pat


Obs num_im num_pat RATE


1 16.0 17 0.94118


2 10.0 12 0.83333


3 4.0 8 0.50000


4 43.0 58 0.74138


5 9.5 10 0.95000


6 25.0 42 0.59524


7 13.0 14 0.92857


8 11.5 12 0.95833


9 22.0 41 0.53659


10 4.0 5 0.80000


11 5.0 6 0.83333


12 18.0 23 0.78261


13 58.0 68 0.85294


14 6.0 10 0.60000


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