Message-ID: <3EC25A2B.2030803@pdf.com>
Date: 2003-05-14T15:00:59Z
From: Spencer Graves
Subject: building mean/median over subgroups
Have you considered "sapply"?
hth. spencer graves
Frank Mattes wrote:
> Dear all,
>
> I'm trying to solve the following problem, and hoping to get some advise
> here from the group
>
> I have a dataframe in which the same sample was measured more than once
> on the same day. I would reorganize the dataframe to get a single value
> (mean /median) for one day
>
> Patient Day Sample Test
> A 1 A 23
> A 1 A 36
> A 5 B 44
> A 5 B 23
> B 2 C 10
> B 2 C 5
>
>
> mean
>
> Patient Day Sample Test.mean
> A 1 A 29.5
> A 5 A 33.5
> B 2 C 7.5
>
>
> it would be great to get some help form the list.
>
> Yours
> Frank