Simple Sample Size Calcs

GMcB

New Member
#1
Hi all, I am looking into the feasibility of mailing (post) churned customers with various long regencies. I want to get an idea of their likely response rates by recency with a small test prior to rolling out to some or all of these regency’s.

Using online calculators or the formula behind these calculators where each cells has say 1000 names, a standard deviation of 0.5, calculated at 95% confidence and 5% margin of error then my sample size appears to be at least 278.

However, is that 278 mailed or 278 responses.

My estimated response rate is only 0.5% at best which would only provide me with 5 responses.

If I need 278 responses I assume I'll need to sacrifice results at recency level to increase volume size ensuring my smallest cell is at least 55,600. Is that correct?

If so the risk is way too high for that kind of volume.

I'm hoping you confirm or correct my thinking and provide any advise please? Thank you.
 

Dason

Ambassador to the humans
#2
I'll admit I haven't thought too much about providing feedback about the other details you've provided but pretty much any sample size calculator will tell you how many actual responses you need at the end of the day.
 

GMcB

New Member
#3
I'll admit I haven't thought too much about providing feedback about the other details you've provided but pretty much any sample size calculator will tell you how many actual responses you need at the end of the day.
Thank you, that’s a great help. Much appreciated.