I am in a doubt about using Absolute and Relative precision for sample size calculations. Suppose if I want to conduct a study to asses the prevalence of Hypertension in a general population, which formula should I use among these two-
$n= Z^2 P(1-P)/d^2$
where $n$ = sample size; $Z$ = C.I.; $P$= anticipated prevalence or prevalence estimated from pilot study and $d$ = absolute precision.
$n = Z^2(1-P) / e^2 P$
Where $e$ = relative precision.
Please suggest me with some example.