Chapter 6, Section 1-D, Exercise 009 Is a Normal Distribution Appropriate? In each case below, is the sample size large enough so that the sample proportions follow a normal distribution?
a) n=600 p=0.2
b) n=20, p=0.4
if np=10 and npq=10 then the data follows normal distribution
a) np= 120,
q= 1-0.2= 0.8
npq= 600 ×0.2×0.4 = 48
Normal distribution is appropriate and sample size is large enough
b) np= 8
q= 1-0.4= 0.6
npq= 20 × 0.4×0.6= 4.8
sample size is not large enough so normal distribution is not appropriate.
