Question

A survey of adults ages? 18-29 found that 93?% use the Internet. You randomly select 132 adults ages? 18-29 and ask them if they use the Internet.?

(a) Find the probability that exactly 125 people say they use the Internet.?

(b) Find the probability that at least 125 people say they use the Internet.?

(c) Find the probability that fewer than 125 people say they use the Internet.

?(d) Are any of the probabilities in parts? (a)-(c) unusual? Explain.

Answer 1

a) The probability that exactly 125 say that they use internet could be computed using binomial probability function as:

Therefore 0.1115 is the required probability here.

b) Probability that at least 125 people say that they use internet is computed here as:

Therefore 0.2875 is the required probability here.

c) The required probability here is computed as:

P(X < 125 ) = 1 - P(X >= 125 ) = 1 - 0.2875 = 0.7125

Therefore 0.7125 is the required probabilities here.

d) None of the above probabilities computed are less than 0.05, therefore none of them are unusual.