3.1 Terminology
Sample spaces, events, complements, unions and intersections, conditional probability notation, and the equally-likely-outcomes model.
26 exercises
3.1 Exercise 1
The sample space S is the whole numbers starting at one and less than 20.
- S = _____________________________
Let event A = the even numbers and event B = numbers greater than 13.
- A = _____________________, B = _____________________
- P(A) = _____________, P(B) = ________________
- A B = ____________________, A OR B = ________________
- P(A B) = _________, P(A B) = _____________
- A′ = _____________,…
3.1 Exercise 2
The sample space S is all the ordered pairs of two whole numbers, the first from one to three and the second from one to four (Example: (1, 4)).
- S = _____________________________
Let event A = the sum is even and event B = the first number is prime. - A = _____________________, B = _____________________
- P(A) = _____________, P(B) = ________________
- A B = ____________________, A B = ______________…
3.1 Exercise 3
A fair, six-sided die is rolled. Describe the sample space S, identify each of the following events with a subset of S and compute its probability (an outcome is the number of dots that show up).
- Event T = the outcome is two.
- Event A = the outcome is an even number.
- Event B = the outcome is less than four.
- The complement of A.
- A B
- B A
- A B
- A B
- A B′
- Event N = the outcome is a prime number. …
3.1 Exercise 4
A number is randomly selected between 1 to 10. Describe the sample space S, identify each of the following events with a subset of S, and compute its probability (an outcome is the number selected).
- Event F = the outcome is 5.
- Event A = the number is more than 6.
- Event B = the number is odd.
- The complement of B.
- A GIVEN B.
- B GIVEN A.
- A OR B.
- A’ OR B.
- Event P = the outcome is a composite number.
- E…
3.1 Exercise 5
the table describes the distribution of a random sample S of 100 individuals, organized by sex assigned at birth and whether they are right- or left-handed.
Let’s denote the events M = the subject is male, F = the subject is female, R = the subject is right-handed, L = the subject is left-handed. Compute the following probabilities:
- P(M)
- P(F)
- P(R)
- P(L)
- P(M R)
- P(F L)
- P(M F)
- P(M R)
- P(F L)
- …
3.1 Exercise 6
The table describes the distribution of a random sample S of 100 individuals, organized by gender and whether they like tea or coffee.
Let's denote the events M = the subject is a man, W = the subject is a woman, T = the subject likes tea, and C = the subject likes coffee. Compute the following probabilities:
- P(M)
- P(W)
- P(T)
- P(C)
- P(M AND T)
- P(W and C)
- P(M OR W)
- P(M OR T)
- P(W OR C)
- P(M')
- P(T|M)
- P(…
3.1 Exercise 7
In a particular college class, there are both men and women students. Some students have long hair and some students have short hair. Write the symbols for the probabilities of the events for parts a through j. (Note that you cannot find numerical answers here. You were not given enough information to find any probability values yet; concentrate on understanding the symbols.)
- Let W be the event tha…
3.1 Exercise 9
Use the following information to answer the next four exercises. A box is filled with several party favors. It contains 12 hats, 15 noisemakers, ten finger traps, and five bags of confetti. One party favor is chosen from the box at random.
Let H = the event of getting a hat.
Let N = the event of getting a noisemaker.
Let F = the event of getting a finger trap.
Let C = the event of getting a bag o…
3.1 Exercise 11
Use the following information to answer the next four exercises. A box is filled with several party favors. It contains 12 hats, 15 noisemakers, ten finger traps, and five bags of confetti. One party favor is chosen from the box at random.
Let H = the event of getting a hat.
Let N = the event of getting a noisemaker.
Let F = the event of getting a finger trap.
Let C = the event of getting a bag o…
3.1 Exercise 13
Use the following information to answer the next six exercises. A jar of 150 jelly beans contains 22 red jelly beans, 38 yellow, 20 green, 28 purple, 26 blue, and the rest are orange. One jelly bean is chosen from the box at random.
Let B = the event of getting a blue jelly bean
Let G = the event of getting a green jelly bean.
Let O = the event of getting an orange jelly bean.
Let P = the event of…
3.1 Exercise 15
Use the following information to answer the next six exercises. A jar of 150 jelly beans contains 22 red jelly beans, 38 yellow, 20 green, 28 purple, 26 blue, and the rest are orange. One jelly bean is chosen from the box at random.
Let B = the event of getting a blue jelly bean
Let G = the event of getting a green jelly bean.
Let O = the event of getting an orange jelly bean.
Let P = the event of…
3.1 Exercise 17
Use the following information to answer the next six exercises. A jar of 150 jelly beans contains 22 red jelly beans, 38 yellow, 20 green, 28 purple, 26 blue, and the rest are orange. One jelly bean is chosen from the box at random.
Let B = the event of getting a blue jelly bean
Let G = the event of getting a green jelly bean.
Let O = the event of getting an orange jelly bean.
Let P = the event of…
3.1 Exercise 19
Use the following information to answer the next six exercises. There are 23 countries in North America, 12 countries in South America, 47 countries in Europe, 44 countries in Asia, 54 countries in Africa, and 14 in Oceania (Pacific Ocean region).
Let A = the event that a country is in Asia.
Let E = the event that a country is in Europe.
Let F = the event that a country is in Africa.
Let N = the e…
3.1 Exercise 21
Use the following information to answer the next six exercises. There are 23 countries in North America, 12 countries in South America, 47 countries in Europe, 44 countries in Asia, 54 countries in Africa, and 14 in Oceania (Pacific Ocean region).
Let A = the event that a country is in Asia.
Let E = the event that a country is in Europe.
Let F = the event that a country is in Africa.
Let N = the e…
3.1 Exercise 23
Use the following information to answer the next six exercises. There are 23 countries in North America, 12 countries in South America, 47 countries in Europe, 44 countries in Asia, 54 countries in Africa, and 14 in Oceania (Pacific Ocean region).
Let A = the event that a country is in Asia.
Let E = the event that a country is in Europe.
Let F = the event that a country is in Africa.
Let N = the e…
3.1 Exercise 25
Use the following information to answer the next six exercises. There are 23 countries in North America, 12 countries in South America, 47 countries in Europe, 44 countries in Asia, 54 countries in Africa, and 14 in Oceania (Pacific Ocean region).
Let A = the event that a country is in Asia.
Let E = the event that a country is in Europe.
Let F = the event that a country is in Africa.
Let N = the e…
3.1 Exercise 27
Use the following information to answer the next six exercises. There are 23 countries in North America, 12 countries in South America, 47 countries in Europe, 44 countries in Asia, 54 countries in Africa, and 14 in Oceania (Pacific Ocean region).
Let A = the event that a country is in Asia.
Let E = the event that a country is in Europe.
Let F = the event that a country is in Africa.
Let N = the e…
3.1 Exercise 31
Use the following information to answer the next ten exercises. On a baseball team, there are infielders and outfielders. Some players are great hitters, and some players are not great hitters.
Let I = the event that a player in an infielder.
Let O = the event that a player is an outfielder.
Let H = the event that a player is a great hitter.
Let N = the event that a player is not a great hitter.
W…
3.1 Exercise 33
Use the following information to answer the next ten exercises. On a baseball team, there are infielders and outfielders. Some players are great hitters, and some players are not great hitters.
Let I = the event that a player in an infielder.
Let O = the event that a player is an outfielder.
Let H = the event that a player is a great hitter.
Let N = the event that a player is not a great hitter.
W…
3.1 Exercise 35
Use the following information to answer the next ten exercises. On a baseball team, there are infielders and outfielders. Some players are great hitters, and some players are not great hitters.
Let I = the event that a player in an infielder.
Let O = the event that a player is an outfielder.
Let H = the event that a player is a great hitter.
Let N = the event that a player is not a great hitter.
W…
3.1 Exercise 37
Use the following information to answer the next ten exercises. On a baseball team, there are infielders and outfielders. Some players are great hitters, and some players are not great hitters.
Let I = the event that a player in an infielder.
Let O = the event that a player is an outfielder.
Let H = the event that a player is a great hitter.
Let N = the event that a player is not a great hitter.
W…
3.1 Exercise 39
Use the following information to answer the next ten exercises. On a baseball team, there are infielders and outfielders. Some players are great hitters, and some players are not great hitters.
Let I = the event that a player in an infielder.
Let O = the event that a player is an outfielder.
Let H = the event that a player is a great hitter.
Let N = the event that a player is not a great hitter.
W…
3.1 Exercise 41
Use the following information to answer the next ten exercises. On a baseball team, there are infielders and outfielders. Some players are great hitters, and some players are not great hitters.
Let I = the event that a player in an infielder.
Let O = the event that a player is an outfielder.
Let H = the event that a player is a great hitter.
Let N = the event that a player is not a great hitter.
W…
3.1 Exercise 43
Use the following information to answer the next ten exercises. On a baseball team, there are infielders and outfielders. Some players are great hitters, and some players are not great hitters.
Let I = the event that a player in an infielder.
Let O = the event that a player is an outfielder.
Let H = the event that a player is a great hitter.
Let N = the event that a player is not a great hitter.
W…
3.1 Exercise 45
Use the following information to answer the next two exercises. You are rolling a fair, six-sided number cube. Let E = the event that it lands on an even number. Let M = the event that it lands on a multiple of three.
What does P(E M) mean in words?
3.1 Exercise 47
Explain what is wrong with the following statements. Use complete sentences.
- If there is a 60% chance of rain on Saturday and a 70% chance of rain on Sunday, then there is a 130% chance of rain over the weekend.
- The probability that a baseball player hits a home run is greater than the probability that he gets a successful hit.
Adapted from Introductory Business Statistics 2e © 2023 Rice University. Licensed under CC BY 4.0. Source: Introductory Business Statistics 2e. Imported at revision 50ec917.