<P> A MissingValue operator. Each missing value in <I>TheTargetAttribute</I> is 
  replaced by the average value of that Column. The operator computes the column 
  statistics if they are not computed yet, which may take some time. 
<P><BR>
<P>
PARAMETERDESCRIPTION
TheInputConcept:inherited
TheTargetAttribute:must be numeric
TheOutputAttribute:inherited
