(12C) Binary Outcome

[Dieter]

(04-08-2018 02:58 AM)Gamo Wrote:  The rule of thumb is based on the assumption of significance α = 0.05 and type II error β = 0.20, i.e. 80% power.

formula:

n = 16P(1-P) / (p1 - p2)^2

where P = p1 + p2 / 2

Where P = (p1 + p2) / 2

Yes, that's the formula in the program. But where do you get the 16 from? For α = 0,05 I think it should be 2 · 1,96² = 7,68. And how do you factor in the β error? Maybe you can deduct the formula step by step – it's been a long time since I handled such things, and I am willing to learn. :-)

So, where does the 16 come from?

Dieter