Where n= required sample size, d= desired absolute precision (0.05), Z =
Multiplier from normal distribution at 95% Confidence interval (1.96),
Pexp = expected prevalence (50%),
(1-Pexp) = Probability of having no disease 50% (0.5).
Accordingly, a total of 384 study populations were sampled from all
three districts. Proportionally, a total of 147, 97, and 140 serum
samples were collected from Asayita, Dubti and Chifra respectively based
on density of cattle population in the study districts.