No, you don't need a certain percentage of the user base. You only need a random sample of a certain absolute size to get the margin of error within a certain limit.
Posted Using LeoFinance Beta
No, you don't need a certain percentage of the user base. You only need a random sample of a certain absolute size to get the margin of error within a certain limit.
Posted Using LeoFinance Beta
What sample size would be appropriate for 200 million plus accounts?
The exact same sample size that would be appropriate for 20 million plus or 2 million plus accounts or 20,000 plus accounts.
It's the sample size itself that matters and the degree to which the sample size is representative i.e. non-biased.
And what size would that be?
It depends on how confident you want to be in your estimate.
You can play with the numbers here, for example:
https://www.surveysystem.com/sscalc.htm