One manufacturer's high-quality product rate is 30%. recently, a sample with size 15 products is collected. among them, 3 are with high quality. Can we say the high-quality rate remains 30% using level of significance (alpha symbol)=0.05 ?
We can find that n(pi)=15 x 0.3 = 4.5 <= 5 (in reality, n(pi) is better be much larger than 5), so we do not take the assumption that it is normally distributed. we cannot use z-test.