[R] Basic stratification calculations

[vito muggeo]

Hi,
if I understand correctly, tapply() is your friend here,

vito

dvrecko at sfu.ca wrote:
> 
> Hi. I'm a student at SFU in Canada. The basic thing I want to do is
> calculate means of different strata. I have 2 vectors. One has the values I
> want to take the means from, the other is the four strata I am interested
> in. So I essentially want to break up the information vector into the four
> strata and calculate four means, one for each stratum. How can I do this in
> a reasonable way?
> 
> 
> Thanks very much.
> Dean Vrecko
> 
> PS: Incidentally I forget how to see the code of functions. Does anyone
> remember the command to do this?
> 
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-- 
====================================
Vito M.R. Muggeo
Dip.to Sc Statist e Matem `Vianelli'
Università di Palermo
viale delle Scienze, edificio 13
90121 Palermo - ITALY
tel: 091 6626240
fax: 091 485726/485612