Question

Sixty-nine percent of US college graduates expect to stay at their first employer for three or more years. You randomly select 18 US college graduates and ask them whether they expect to stay at their first employer for 3 or more years. Find the probability that the number who expect to stay at their employer for three or more years is (a) Exactly six people (b) Less than 7 and (c) at least 15. Identify any unusual events Explain

Answer 1

Let X = No. of college graduates expect to stay at their first employer for three or more years.

n = 18. and p = 69% = 0.69

X follows Binomial distribution with parameter n and p.

The pmf of X is,

q = 1-p

a.

b.

c.