Question

Make a tree diagram to show all possible sequences of answers for three multiple-choice questions, each with four possible responses. Assuming that you are guessing the answers so that all outcomes listed in the tree are equally likely, what is the probability that you will guess the one sequence that contains all three correct answers?

A researcher team at Cornell University conducted a study that approximately 10% of all businessmen who wear ties wear them so tightly that they reduce blood flow to the brain diminishing cerebral functions. At a board meeting of 25 businessmen, all of whom wear ties, what is the probability that (this is binomial distribution problem with n=25, p=0.1)

i. at least 1 tie is too tight

ii. at least 24 ties are too tight

Answer 1

mOHdo fet a question ha 4 possile alriey (A,8,C each wilthi 4 pot ri ble optims There 3 questi on are 31, Total no. possibilities =4° = 64 Bnly Seguena is porsible for corsast- aut wes one 64 U for mula PCx - x) = n-1 ; x=0, 1,2 --. U) P(x21) = 1- P(メ=0) 25 0.9282 P (x>24) = P(X=24) + P (x =25) - (E) 1a,5"09)' + ( )ca3"c09° 24 %3D (0.9) -23 = 2. 26 x10 0.000