Re: power calculation

Thanks for the help
in answer to your questions
0.017 comes from the significant alpha value /3 bonferroni correction
as there was 3 groups in the pilot study counducted, which is where the
mean difference sd & sem come from.
As I only really need to know the number of subjects required to gain
statistical significance between my 2 intervention groups, the other
group was a control of such.
Think I have it now!
I wanted to know how to work it out properly without using the packages
available

.