Comments on The Scientific Marketer: Miró's Control Group Size Calculator Now Available...

OK thanks. But what tipped me off is the label bel...

2010-03-01T13:24:39.537Z

OK thanks. But what tipped me off is the label below (I increased the sizes to get a solution). Maybe just these labels are reversed? (I entered 4 in the box entitled "Smallest expected uplift (T – C)") and it appears as "max CG rate".

Fleiss sizes (pop = 25,000 min uplift = 25.00% max CG rate = 4.00%):

Hi Brian I think it's OK. The reason it rep...

2010-02-27T14:39:08.320Z

Hi Brian

I think it's OK. The reason it reports N/A is because 540 isn't a large enough population size to allow you to detect a 4 percentage point uplift against a control rate of 24% (i.e. treated 28%, control 24%). It gives a result when you swap the figures because you don't need much of a population to have confidence that a rate an observed rate in the treatment group of 28% is significantly different from an observed rate in the control group of 4%.

Hope that helps.

I dont think this is working. Entering for example...

2010-02-26T23:57:32.837Z

I dont think this is working. Entering for example:

pop size of 540 and T-C=4 and highest likely rate in control group =24 yields no answer. But if I switch T-C and control group I get answer. Are the two labels switched?