[R] Welch Two Sample T-Test

[Jose Iparraguirre]

Let's define this object:

> welch <- t.test(x,y,alt="less",var.equal=TRUE)

Then, if you type

> names(welch)

You get its contents:

[1] "statistic"   "parameter"   "p.value"     "conf.int"    "estimate"   
[6] "null.value"  "alternative" "method"      "data.name"

Now, to obtain the value of each of its elements, you use the '$' sign, as in:

> welch$statistic
        t 
-0.533114 
> welch$parameter
df 
18

Etc.

Hope this helps,

José


José Iparraguirre
Chief Economist
Age UK

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-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of cosworth201
Sent: 07 November 2012 15:27
To: r-help at r-project.org
Subject: [R] Welch Two Sample T-Test

I know when I enter this into R:
> x = c(15, 10, 13, 7, 9, 8, 21, 9, 14, 8)
> y = c(15, 14, 12, 8, 14, 7, 16, 10, 15, 12)
> t.test(x,y,alt="less",var.equal=TRUE)

it shows:

        Two Sample t-test

data:  x and y 
t = -0.5331, df = 18, p-value = 0.3002
alternative hypothesis: true difference in means is less than 0 
95 percent confidence interval:
     -Inf 2.027436 
sample estimates:
mean of x mean of y 
     11.4      12.3 


I need to write out the entire function and give this same result but
without t.test(x,y,alt="less",var.equal=TRUE). I need to print out the value
for t, df, pvalue as well as the confidence, etc. How exactly do I go about
doing that?



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