Point estimate for the difference between two population proportions is the difference between the two sample proportions, written as:
and the standard deviation is given by
When np and n(1-p) is greater than 5, then the sampling distribution is approximately normal and we can use standard normal methods.
Thus, the propability of a test <span>for the difference between two population proportions is given by
</span>
and the standard deviation is given by
When np and n(1-p) is greater than 5, then the sampling distribution is approximately normal and we can use standard normal methods.
Thus, the propability of a test <span>for the difference between two population proportions is given by