[R] Importing Data for a two sample t-test

[arun]

Hi,

Not sure why you wanted to separate A and B for a two sample t-test.
dat1<-read.table(text="
weights  company
1                  A
2                  A 
2                  B
3                  B
",sep="",header=TRUE,stringsAsFactors=FALSE)
 t.test(weights~company,data=dat1)

#    Welch Two Sample t-test
#
#data:  weights by company 
#t = -1.4142, df = 2, p-value = 0.2929
#alternative hypothesis: true difference in means is not equal to 0 
#95 percent confidence interval:
 #-4.042435  2.042435 
#sample estimates:
#mean in group A mean in group B 
  #          1.5             2.5 

In case, you wanted to separate A and B:
library(reshape2)
dcast(dat1,weights~company,value.var="weights")
#  weights  A  B
#1       1  1 NA
#2       2  2  2
#3       3 NA  3

Hope it helps.

A.K.



----- Original Message -----
From: nilsonern <Nilsonern at gmail.com>
To: r-help at r-project.org
Cc: 
Sent: Wednesday, November 14, 2012 11:52 PM
Subject: [R] Importing Data for a two sample t-test

I am trying to do a two sample t-test with data that i received in a text
document.  one list has the slab weights and the second has the company it
is associated with.  here is an example.

weights  company
1                  A
2                  A  
2                  B
3                  B

I was able to import the data but i cannot figure out how separate the data. 
I want to put them in two separate sets, one being A and one being B.  Any
help would be appreciated.  Thanks.



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