Checklist for Use of Sample Size formula
The formula to determine your sample size :
n = [4 (r) (1 - r) (f) (1.1)] / [(.12r)2 (p) (nh)].
Use it if any (one or more) of the following applies in your country:
p – the proportion of one-year-old children is other than 3%
nh – the average household size is less than 4.5 persons or greater than 6.5
r – the coverage rate of your key indicator is under 20 or over 40 percent
f - the sample design effect for your key indicator is different from 1.5, according to accepted estimates from other surveys in your country
your anticipated non-response rate is more or less than 10 percent.