SEˆp=√ˆp(1-ˆp)n
m=z*SEˆp
where z* is the value for the standard Normal density curve with area C between -z* and z*.
ˆp±m
We recommend using this method when the number of successes and the number of failures are both at least 10.
z=ˆp-p0√p0(1-p0)n
with P-values calculated from the N(0,1) distribution. Use this test when the expected number of successes np0 and the expected number of failures n(1-p0) are both at least 10.
n=(z*m)2p*(1-p*)
where p* is a guessed value for the proportion, and z* is the standard Normal critical value for the desired level of confidence. To ensure that the margin of error of the interval is less than or equal to m no matter what ˆp may be, use
n=(z*2m)2