[R] Cannot calculate mean() for double vector

[Ista Zahn]

On Fri, Oct 16, 2009 at 2:01 PM, Reuben Bellika <rubenyi at gmail.com> wrote:
> OK. It looks like I just have several NA values at the start of my array:
>
>> which (is.na(x_ema))
> [1] 1 2 3 4 5 6 7 8 9
>
> That make sense, because the moving average is not defined for those
> positions. I'll just have to set those values to zero:
>
>> x_ema = replace(x_ema, which(is.na(x_ema)), 0)


Nooooo! Your mean is now biased toward zero!

see ?mean and read the part about na.rm.

-Ista

>> which (is.na(x_ema))
> integer(0)
>
> The mean() call works now and I can get on with my work. I'll have to
> remember to condition the data like this in the future.
>
> Thanks for the help!
>
> Reuben Bellika
>
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-- 
Ista Zahn
Graduate student
University of Rochester
Department of Clinical and Social Psychology
http://yourpsyche.org