massmatics,

You are trying to take the mean/sd of an entire data.frame and therefore

you receive an error. You must do some form of subset and take the mean of

the 'breaks' column. This can be done a few ways (as with almost anything

in R).

AM.warpbreaks2 <- subset(AM.warpbreaks, breaks <= 30)

mean(AM.warpbreaks2$breaks)

or

mean(AM.warpbreaks$breaks[Am.warpbreaks$breaks <= 30])

or more concisely

with(AM.warpbreaks, mean(breaks[breaks <= 30]))

Again, the main point here is that you need to specify the column when

working with a data.frame object.

Regards,

Charles

On Fri, Sep 11, 2015 at 11:02 AM, Tom Wright <

[hidden email]> wrote:

> On Fri, 2015-09-11 at 07:48 -0700, massmatics wrote:

> > AM.warpbreaks<=30

>

> The above command is not returning what you expected, what part of the

> AM.warpbreaks dataframe is expected to be <= 30?

>

> Effectively you are using a two stage process.

> 1) Create a logical vector identifying rows in the dataframe with a

> breaks value <= 30

> 2) use the vector in 1. to extract just the rows you are interested in

> and use that to calculate the mean of the breaks column.

>

> ______________________________________________

>

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https://stat.ethz.ch/mailman/listinfo/r-help> PLEASE do read the posting guide

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[hidden email] mailing list -- To UNSUBSCRIBE and more, see

https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide

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