United Airlines' flights from Denver to Seattle are on time 50 % of the time. Suppose 9 flights are randomly selected, and the number on-time flights is recorded. Round answers to 3 significant figures.

(a) The probability that exactly 4 flights are on time is =

(b) The probability that at most 3 flights are on time is =

(c) The probability that at least 8 flights are on time is =

Guest Feb 9, 2020

#1**0 **

1) Exactly 4 of 9: _{9}C_{4} · (0.50)^{4} · (0.50)^{5}

2) At most 3 of 9: _{9}C_{0} · (0.50)^{0} · (0.50)^{9} + _{9}C_{1} · (0.50)^{1} · (0.50)^{8} · _{9}C_{2} · (0.50)^{2} · (0.50)^{7} · _{9}C_{3} · (0.50)^{3} · (0.50)^{6}

3) At least 8: _{9}C_{8} · (0.50)^{8} · (0.50)^{1} + _{9}C_{9} · (0.50)^{9} · (0.50)^{1}

geno3141 Feb 9, 2020