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    DATA MINING
     Desktop Survival Guide by Graham Williams  | 
    
    
     
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Imputation | 
Multiple imputation (MI) is a general purpose method for handling of
missing data. The basic idea is: Impute missing values using an
appropriate model that incorporates random variation; Do this 
times (often 3-5 times) to obtain 
 datasets, all with no missing
values; Do the intended analysis on each of these datasets; Gert the
average values of the parameter estimates across the 
 samples to
have a single point estimate; Calculate standard errors by firstly
averaging the squared standard errors of the 
 estimates and 
calculating the variance of the 
 parameter estimates across
samples, and then combine these in some way.
There are a number of R packages for imputation.