[R] How to apply a function to every element of a dataframe, when the function uses for each colummn and row different values to calculate with?

[peter dalgaard]

On Aug 21, 2013, at 00:01 , David Winsemius wrote:

> 
>  fmat <- (abs(x - E) )^2/E
> 
> (I'm not sure why that abs is in the `chisq.test` code.)

A bit of a misquote there; chisq.test has

            STATISTIC <- sum((abs(x - E) - YATES)^2/E)

The abs() ensures that the Yates correction is towards zero.

(a few lines above, we have

                YATES <- min(0.5, abs(x - E))

which avoids the embarrassment of a positive chi-square when x==E).

If YATES==0, he squaring of course makes abs() superfluous. 

-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com