Question

1. Research indicates that 2,118 out of 100,000 Americans live to age 100 or older. What is the probability of selecting an American at random and finding that he/she does not live to age 100?
2. The Grand Theater uses teams of three to work the concession stand each evening. There are seven employees available to work each evening. What counting rule would allow use to figure out how many teams can be scheduled to staff the concession stand? Why?
3. A trucking company has a 95% on time arrival rate. What is the probability of looking at this company’s last 50 deliveries and exactly 49 arrive on time?

Answer 1

1. P(living to age 100 or older) = 2118/ 100000 = 0.02118

P( not living to age of 100 or older) = 1- 0.02118 = 0.9788

2. 3 workers can be selected from 7 in 7C3 ways

To form the teams we use combinations rule as it shows how many different possible groups/ subsets can be made from larger set. We dont use permuations as the order of employees choosen does not matter.

3. P(arriving on time) = 0.95

P(x=49)

  

P(x=49) = 0.2025