What is the variance of this combined proportion
phat12= n1phat + n2phat2 / n1 +n2?
n1 and n2= sample size
x1 and x2= n.o of tall people in each sample
let phat1 = x1/n1 and phat2 = x2/n2 denote the sample proportion of tall people in each sample
phat12= n1phat + n2phat2 / n1 +n2?
n1 and n2= sample size
x1 and x2= n.o of tall people in each sample
let phat1 = x1/n1 and phat2 = x2/n2 denote the sample proportion of tall people in each sample