Statalisters -
I am interested in obtaining the standard deviation for a particular
variable with groups determined by another variable. Essentially I would
like to combine the 'egen std()' function with the 'by' construct which is
not allowed. Is there an alternative to using collapse (I would prefer not
to change the dataset) or having to introducing a matrix?
Assume:
Manuf Model Class Mpg
Chevy Tahoe SUV 14
Toyota Highlander SUV 19
Toyota Camry Auto 23
Ford F-150 P/U 17
etc.
I would like to capture the standard deviation of the mpg within a
particular class.
i.e.
sort class
by class: gen (or egen) mpgstd = std(mpg)
The error is:
. by obj: egen mpgstd = std(mpg)
egen ... std() may not be combined with by
This however, is not allowed. Any thoughts or comments are greatly
appreciated.
Steve Fraser
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