R help - Jun 2013 - sample size determination - comparing means for different size samples

Looking to determine sample sizes for both my experimental and control
groups (I want only a small portion of my participants in my experimental
condition) in order to compare population means. I would be able to
estimate standard deviation beforehand.

I'm using the bpower function from the Hmisc R package, specifically
bsamsize to compare population proportions, but was wondering if there was
an equivalent function for comparing means.

-- 
Rebecca Greenblatt

	[[alternative HTML version deleted]]

This is a duplicate question, right?

On Jun 6, 2013, at 12:58 PM, Rebecca Greenblatt wrote:
> Looking to determine sample sizes for both my experimental and control
> groups (I want only a small portion of my participants in my experimental
> condition) in order to compare population means. I would be able to
> estimate standard deviation beforehand.
> 
> I'm using the bpower function from the Hmisc R package, specifically
> bsamsize to compare population proportions, but was wondering if there was
> an equivalent function for comparing means.
> 
> -- 
> Rebecca Greenblatt
> 
> 	[[alternative HTML version deleted]]
> 
David Winsemius
Alameda, CA, USA

Hello,

At an R prompt, type

?power.t.test

Hope this helps,

Rui Barradas

Em 06-06-2013 20:58, Rebecca Greenblatt escreveu:
> Looking to determine sample sizes for both my experimental and control
> groups (I want only a small portion of my participants in my experimental
> condition) in order to compare population means. I would be able to
> estimate standard deviation beforehand.
>
> I'm using the bpower function from the Hmisc R package, specifically
> bsamsize to compare population proportions, but was wondering if there was
> an equivalent function for comparing means.
>