Message-ID: <405CBA2B-A3B7-4407-A1C3-BF19800F7167@comcast.net>
Date: 2012-12-25T21:37:45Z
From: David Winsemius
Subject: apply with missing values
In-Reply-To: <1356376908783-4653889.post@n4.nabble.com>
On Dec 24, 2012, at 11:21 AM, jenna wrote:
> I am trying to get the means of each participants avg saccade
> amplitude as a
> function of the group they were in (designated by "shape_"), but
> there are
> missing values in the dataset....this is what i tried...
>
> with(data055,tapply(AVERAGE_SACCADE_AMPLITUDE,shape_,mean))
> i get an error saying the argument is not numerical or logical
The error message appears informative (and would NOT be expected to be
solved by adding na.rm=TRUE). Your construction of the data055
dataframe was flawed in some way. You have not shown how it was done
nor given dput(head(data055)) which would have provided a basis for
further assessment. Based on past experience my guess is that there
was a character value in the column of data you thought was numeric
during a read.* operation and is now a factor.
>
> next i try...
>
>> 055 <- tapply(data055$AVERAGE_SACCADE_AMPLITUDE,
> + data055$shape_,mean, na.rm =TRUE)
>
> still nothing....
--
David Winsemius, MD
Alameda, CA, USA