For calculation of sample size for a prevalence study all of the following are necessary except
(A) Prevalence of disease in population (B) Power of the study (C) Significance level (D) Desired precision
(D) Sample size depends upon:

The effect size (usually the difference between 2 groups).
The population standard deviation (for continuous data).
The desired power of the experiment to detect the postulated effect (Power = 1 – b)
The significance level.