A study ofcommunity college enrollments in a certain state finds that 60% of all

Question

A study ofcommunity college enrollments in a certain state finds that 60% of all full-time undergraduates are under 20 years of age. 6. a. If a random sample of four community college students is selected from this state, find the probability that at least three of the students are under 20 years of age. Consider a random sample of 15 community college students from this state i. What is the expected number of students under 20 years of age? ii. What is the standard deviation of the number of students under 20 years of age? c. For the situation described in part b, is it appropriate to use the normal approximation to estimate the probability of getting at least 12 students who are under the age of 20? Explain.

Explanation / Answer

6 Solution:-

a. P(3) = (4C3) * ( .6 )^3 * .4 = .3456
P(4) = (.6)^4 = .1296

P(at least 3) = P(3) + P(4) = .4752

b. i => n*p = 15*0.6 = 9

ii => sqrt(n*p*q) = sqrt(15*0.6*0.4) = 1.8973

c.  Pr[X > 12] = 1 - Pr[X <= 11]

=  0.0271

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.