Message-ID: <008601c23a47$35c49580$0201a8c0@MARC>
Date: 2002-08-02T17:08:21Z
From: Marc Schwartz
Subject: extracting data from a dataframe
In-Reply-To: <20020802153146.GA3619@isis.visi.com>
> -----Original Message-----
> Hi everyone,
>
> Here's a question about extracting data from a dataframe:
>
> Let's say I've got a dataframe with two vectors, TEST and GENDER.
> GENDER
> contains a 1 for males and 2 for females. I want to separate the
results
> of TEST by GENDER so I can compare their means.
>
> What's the most efficient way to do this with R?
>
> -Tim
Presuming that you wish to perform a two-sample t-test on the means, you
don't need to actually "split" the dataframe. You could use the formula
method for t.test() by the following:
t.test(df$TEST ~ df$GENDER)
where df is the name of your dataframe.
If you actually want to split the dataframe, see ?split.
HTH.
Marc
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