The normal approximation to a binomial can be used for a significance test on the population proportion p if np > 15.
a. n = 10 and H0: p = 0.4. => np = 10(0.4) = 4 [can not be used]
b. n = 100 and H0: p = 0.6. => np = 100(0.6) = 60 [can be used]
c. n = 1000 and H0: p = 0.996. => np = 1000(0.996) = 996 [can be used]
d. n = 500 and H0: p = 0.3. => np = 500(0.3) = 150 [can be used0