[R] Weighted SD

[Thomas Lumley]

On Mon, 1 Feb 2010, David Winsemius wrote:

>
> On Feb 1, 2010, at 12:37 PM, Антон Морковин wrote:
>
>> Dear all,
>> what function can be used to calculate weighted SD or/and SE¿
>>
>> There's no such stuff in 'base' package.
>
> Seems as though lm with a weights argument could be used fairly simply.
>

As I have pointed out from time to time, it depends on what the weights are for -- are they precision weights, which lm() can handle, or sampling weights, which it can't?

      -tomas

Thomas Lumley			Assoc. Professor, Biostatistics
tlumley at u.washington.edu	University of Washington, Seattle