Answer to Question #205143 in Statistics and Probability for Shema Derrick

Question

If the probability is 0.1 that a person will make a mistake on his or her state income tax return, find the probability that: a) four totally unrelated persons each make a mistake b) Mr. Jones and Ms. Clark both make a mistake and Mr. Roberts and Ms. Williams do not make a mistake.

Answer 1

We will use the binomial distribution with parameters 4 and 0.1.

a). The probability is $(0.1)^4$.

b). $C_4^2(0.1)^2(0.9)^2=\frac{4!}{2!2!}(0.1)^2(0.9)^2\approx0.049$