Cochran Formula Reference. The variance reduces to Vy I s2Nn 1 I wsh2 58 Corollary 3. The formula developed yields values slightly higher than one recently proposed by Muoz and Rosner 1984 Biometrics.
This formula applies also to the difference between two ratios R and Rk. November 2013 Analysis of sample size in consumer surveys GfK Polonia 3 1. N z 2 p 1 p e 2 I have found multiple resources that describe p as a sample proportion or as estimated proportion of an attribute that is present in the population.
Z p 1 p n W 2 displaystyle Z sqrt frac p.
The best way to answer the question is to check the original publication. Sampling Techniques 2nd Ed New York. Has been cited by the following article. N Z 2 W 2 displaystyle n frac Z 2 W 2 in the case of using 5 as the most conservative estimate of the proportion.
