3.
A population N is divided into three strata so that N1 = 5000, N2 = 2000and N3 = 3000. Respective standard deviations are: σ1 = 15, σ2 = 18, and σ3 = 5. How should a sample of size n = 84 be allocated to the three strata, if we want optimum allocation using disproportionate sampling design?
A:
n1=50,n2=10andn3 =24
B:
n1=28,n2=28andn3 =28
C:
n1=50,n2=24andn3 =10
D:
n1=54,n2=10andn3 =20
The answer is:
C
