Message-ID: <4EC6535C.6080801@uky.edu>
Date: 2011-11-18T12:45:16Z
From: Patrick Breheny
Subject: Fisher Exact Test
In-Reply-To: <CAJ-4XApZnfOnHQdikgvzYzrtheZMWiV8Ty2MRvR7Z+qzGh9e4Q@mail.gmail.com>
On 11/17/2011 06:29 PM, Abraham Mathew wrote:
> I have information on two versions of the same site, and I have data
> on the number of times people filled out a form on each version
> of the site.
>
> Sample data:
>
> Site 1 Site 2
> Filled out form 10 35
>
> Did not fill out form 50 40
>
>
> dat2 = matrix(c(10,50,35,40), ncol=2)
> dat2
> fisher.test(dat2)
>
>> fisher.test(dat2)
> Fisher's Exact Test for Count Data
>
> data: dat2
> p-value = 0.0002381
> alternative hypothesis: true odds ratio is not equal to 1
> 95 percent confidence interval:
> 0.09056509 0.54780215
> sample estimates:
> odds ratio
> 0.2311144
>
>
> I'm really not sure if I set up the test properly, but I can
> obviously reject the null hypothesis given the low p-value.
> Site 2 converts better than site 2 at a statistically significant
> threshold.
>
> Am I running my code wrong?
Your code is fine; your conclusion is valid (assuming you mean
"...better than site 1...").
--
Patrick Breheny
Assistant Professor
Department of Biostatistics
Department of Statistics
University of Kentucky