Question

Suppose approximately 75% of all marketing personnel are extroverts, whereas about 55% of all computer programmers are introverts. (Round your answers to three decimal places.)

(a) At a meeting of 15 marketing personnel, what is the probability that 10 or more are extroverts?

What is the probability that 5 or more are extroverts?

What is the probability that all are extroverts?

(b) In a group of 5 computer programmers, what is the probability that none are introverts?

What is the probability that 3 or more are introverts?

What is the probability that all are introverts?

Answer 1

Part a)

X ~ B ( n = 15 , P = 0.75 )

i)

P ( X >= 10 )

P ( X >= 10 ) = 0.8516

ii)

P ( X >= 5 ) = 1 - P ( X <= 4 )

P ( X >= 5 ) = 0.9998

iii)

Part b)

X ~ B ( n = 5 , P = 0.55 )

i)

ii)

P ( X >= 3 )

P ( X >= 3 ) = 0.5931

iii)