Download Quiz 4.1 - 4.3 Review

College Prep. Stats.
Sections 4.1 – 4.3 Quiz Review
Name: _________________________________
Round all probability answers to four decimal places, unless otherwise specified!
1. Describe the following terms in your own words: event, simple event, sample space, disjoint, compound event, and complementary
events.
2. Express the indicated degree of likelihood as a probability value. “There is a 67% chance of thunderstorms tomorrow”
3. What two values does a probability lie between?
4. What probability values are considered unusual?
5. A drawer contains 7 red socks, 6 blue socks, and 3 green socks. If a sock is randomly selected from the box,
a) What is the probability that it is red?
b) What is P(not red)?
6. If P(A and B) = 0, are the events disjoint or not disjoint?
7. P(A) = 0.33, P(B) = 0.66, and P(A and B) = 0.22, find P(A or B).
8. A multiple choice question has 17 possible answers, only one of which is correct. Is it "unusual" to answer a question correctly if a
random guess is made?
9. A sample space consists of 146 separate events that are equally likely. What is the probability of each?
10. A bag contains 4 red marbles, 3 blue marbles, and 7 green marbles. If a marble is randomly selected from the bag, what is the
probability that it is blue?
11. A bag contains 6 red marbles, 3 blue marbles, and 5 green marbles. If a marble is randomly selected from the bag, what is the
probability that it is not blue?
12. Of 1735 people who came into a blood bank to give blood, 373 people had high blood pressure. Estimate the probability that the
next person who comes in to give blood will have high blood pressure.
13. If a person is randomly selected, find the probability that his or her birthday is not in December. Ignore leap years.
14. a) If P(A) = 0.81, P(B) = 0.25, and P(A or B) = 0.91, find P(A and B).
b) Find P(A or B) if P(A) = 0.11, P(B) = 0.07, and P(A and B) = 0.05.
Use the following information to answer questions 15 – 17:
A study of consumer smoking habits includes 196 people in the 18 – 22 age bracket (43 of whom smoke), 148 people in the 23 – 30
age bracket (37 of whom smoke), and 96 people in the 31 – 40 age bracket (23 of whom smoke). (HINT: fill in the table first)
18 – 22
23 – 30
31 – 40
Smoke
Does not smoke
15. If one person is randomly selected from this sample, find the probability of getting someone who smokes.
16. If one person is randomly selected from this sample, find the probability of getting someone who is age 23 – 30 or smokes.
17. If one person is randomly selected from this sample, find the probability of getting someone who is 31 – 40 or does not smoke.
18. A roulette wheel has 38 slots. One slot is 0, another is 00, and the others are numbered 1 through 36. You place a bet that the
outcome is a black slot.
a) Find the probability of winning.
b) Find the actual odds against winning.
c) If the payoff odds were the actual odds found in part (b), how much would a $22 bet be worth?
19. A roulette wheel has 38 slots. Two green slots are labeled 0 and 00. The other slots are numbered 1 through 36 and are evenly
distributed between red and black. You place a bet that the outcome is a odd slot.
a) Find the probability of winning.
b) Find the actual odds against winning.
c) If the payoff odds are the actual odds found in part b), how much would a $22 bet be worth?
20. Men have XY (or YX) chromosomes and women have XX chromosomes. X-linked recessive genetic diseases occur when there is
a defective X chromosome that occurs without a paired X chromosome that is good. In the following problems, represent a defective
X chromosome with a lower case x, so a child with the xY or Yx pair of chromosomes will have the disease, while the child with XX
or XY or YX or xX or Xx will not have the disease. Each parent contributes one chromosome to the child.
a) If a father has the defective x chromosome and the
mother has good XX chromosomes, what is the probability
that a daughter will inherit the disease?
Write out the entire sample set.
b) If a mother has one defective x chromosome and one good
X chromosome, and the father has good XY chromosomes,
what is the probability that a son will inherit the disease?
Write out the entire sample set
mother
mother
father
x
Y
x
X
X
father
X
Y
X