MATH 221 Week 2 Homework; Statistics for Decision-Making

1. Question: According to company records, the probability that a washing machine will break in the first year is 4%. This would be considered: 2. Question: Given the following information, find the probability that a randomly selected student will be very short. Number of students who are very short: 45, short: 60, tall: 82, very tall: 21 3. Question: Given the following information, find the probability that a randomly selected dog will be a golden retriever or a poodle. Number of dogs who are poodles: 31, golden retrievers: 58, beagles: 20, pugs: 38 4. Question: Given that there is a 21% chance it will rain on any day, what is the probability that it will rain on the first day and be clear (not rain) on the next two days? 5. Question: Consider the following table. What is the probability of blue? 6. Question: Consider the following table. What is the probability of red, given yes? 7. Question: A card is randomly selected from a standard deck of 52 cards. What is P(face card)? 8. Question: In a sample of 500 customers, 140 say that service is poor. You select two customers without replacement to get more information on their satisfaction. What is the probability that both say service is poor? 9. Question: In a sample of 528 customers, 484 say they are happy with the service. If you select three customers without replacement for a commercial, what is the probability they will all say they are happy with the service? 10. Question: A company finds that when they pay employees more, the employees are more productive. How would you classify these events, based on this finding? 11. Question: A company sells 14 types of crackers that they label varieties 1 through 14, based on spice level. What is the probability that one purchase results in a selection of a cracker with an even number or a number less than 5? 12. Question: Of the shirts produced by a company, 6.5% have loose threads, 9.5% have crooked stitching, and 3% have loose threads and crooked stitching. Find the probability that a randomly selected shirt has loose threads or has crooked stitching. 13. Question: Randomly select a customer that is happy with the company. Randomly select a customer who is elderly. Are these events mutually exclusive? 14. Question: In a sample of 800 adults, 242 said that they liked sugar cereals. Three adults are selected at random without replacement. Find the probability that all three like sugar cereals. 15. Question: In a sample of 80 adults, 28 said that they would buy a car from a friend. Three adults are selected at random without replacement. Find the probability that none of the three would buy a car from a friend. 16. Question: A sock drawer has 17 folded pairs of socks, with 5 pairs of white, 8 pairs of black and 4 pairs of blue. What is the probability, without looking in the drawer, that you will first select and remove a black pair, then select either a blue or a white pair? 17. Question: An investment advisor believes that there is a 60% chance of making money by investing in a specific stock. If the stock makes money, then there is a 50% chance that among those making money, they would also get a dividend. Find the probability that the investor makes money and receive a dividend. 18. Question: An investment advisor believes that there is a 60% chance of making money by investing in a specific stock. If the stock makes money, then there is a 50% chance that among those making money, they would also get a dividend. Find the probability that the investor makes money but does not receive a dividend. 19. Question: A smart phone company found in a survey that 6% of people did not own a smart phone, 15% owned a smart phone only, 26% owned a smart phone and only a tablet, 32% owned a smart phone and only a computer, and 21% owned all three. If a person were selected at random, what is the probability that the person would own a smart phone only or a smart phone and computer only? 20. Question: Match the terms and their definitions: • 0 and 1 (Probability is between) • 1 - P(E) (Complement of an event) • The occurrence of one event does not affect the occurrence of the other (Independent events) • Cannot occur at the same time ( Mutually exclusive events) • Probability of an event given that another event has occurred ( Conditional probability)