R help - Nov 2010 - Sample size with ANCOVA

Dear R users:

          How to calculate the sample size with ANCOVA? For example, in a
clinical trial, the correlation between the baseline and one-year follow-up
blood pressure is 0.7, with a standrad devision 15, in order to detect a 10
difference between baseline and follow-up with a power = 0.9, and alpha 0.05?
Then, how to calculate the sample size with the correlation of 0.7
between baseline and follow-up?

    Thanks and regards,

     Xing

	[[alternative HTML version deleted]]

On Nov 20, 2010, at 8:31 AM, XINLI LI wrote:
> Dear R users:
> 
>          How to calculate the sample size with ANCOVA? For example, in a
> clinical trial, the correlation between the baseline and one-year follow-up
> blood pressure is 0.7, with a standrad devision 15, in order to detect a 10
> difference between baseline and follow-up with a power = 0.9, and alpha
> 0.05? Then, how to calculate the sample size with the correlation of 0.7
> between baseline and follow-up?
> 
>    Thanks and regards,
> 
>     Xing

See this post from this past July:

  https://stat.ethz.ch/pipermail/r-help/2010-July/245656.html

HTH,

Marc Schwartz