Question

Consider a binomial random variable X with n = 7 and p = 0.3. What is the P(X = 3) *

0.126

1.47.

2.1

0.874

0.227

Answer 1

$$P(X=3)=\dbinom{7}{3}(0.3)^3(1-0.3)^{7-3}$$ $$=\dfrac{7!}{3!(7-3)!}(0.3)^3(0.7)^{4}\approx0.2269$$

0.227