INSTRUCTOR ANSWER GUIDE
OpenStax Introductory Business Statistics 2e
Instructor Answer Guide
,OpenStax Introductory Business Statistics 2e
Instructor Answer Guide
CHAPTER 3: PROBABILITY TOPICS
Exercise 1. 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 that a student is a woman.
• Let M be the event that a student is a man.
• Let S be the event that a student has short hair.
• Let L be the event that a student has long hair.
a. The probability that a student does not have long hair.
b. The probability that a student is a man or has short hair.
c. The probability that a student is a woman and has long hair.
d. The probability that a student is a man, given that the student has long hair.
e. The probability that a student has long hair, given that the student is a man.
f. Of all the women students, the probability that a student has short hair.
g. Of all students with long hair, the probability that a student is a woman.
h. The probability that a student is a woman or has long hair.
i. The probability that a randomly selected student is a man with short hair.
j. The probability that a student is a woman.
Solution a. P(L′)=P(S)
b. P(M OR S)
c. P(W AND L)
d. P(M|L)
e. P(L|M)
f. P(S|W)
g. P(W|L)
h. P(W OR L)
i. P(M AND S)
j. P(W)
Exercise 2. 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 of confetti.
Find P(H).
Solution
2
October 28, 2025
,OpenStax Introductory Business Statistics 2e
Instructor Answer and Solution Guide
Chapter 3: Probability Topics
Exercise 3. 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 of confetti.
Find P(N).
Solution
P(N) =
Exercise 4. 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 of confetti.
Find P(F).
Solution
P(F) =
Exercise 5. 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 of confetti.
Find P(C).
Solution
P(C) =
Exercise 6. 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 getting a purple jelly bean.
3
October 28, 2025
, OpenStax Introductory Business Statistics 2e
Instructor Answer Guide
Let R = the event of getting a red jelly bean.
Let Y = the event of getting a yellow jelly bean.
Find P(B).
Solution
P(B) =
Exercise 7. 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 getting a purple jelly bean.
Let R = the event of getting a red jelly bean.
Let Y = the event of getting a yellow jelly bean.
Find P(G).
Solution
P(G) =
Exercise 8. 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 getting a purple jelly bean.
Let R = the event of getting a red jelly bean.
Let Y = the event of getting a yellow jelly bean.
Find P(P).
Solution
P(P) =
Exercise 9. 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 getting a purple jelly bean.
Let R = the event of getting a red jelly bean.
4
October 28, 2025
OpenStax Introductory Business Statistics 2e
Instructor Answer Guide
,OpenStax Introductory Business Statistics 2e
Instructor Answer Guide
CHAPTER 3: PROBABILITY TOPICS
Exercise 1. 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 that a student is a woman.
• Let M be the event that a student is a man.
• Let S be the event that a student has short hair.
• Let L be the event that a student has long hair.
a. The probability that a student does not have long hair.
b. The probability that a student is a man or has short hair.
c. The probability that a student is a woman and has long hair.
d. The probability that a student is a man, given that the student has long hair.
e. The probability that a student has long hair, given that the student is a man.
f. Of all the women students, the probability that a student has short hair.
g. Of all students with long hair, the probability that a student is a woman.
h. The probability that a student is a woman or has long hair.
i. The probability that a randomly selected student is a man with short hair.
j. The probability that a student is a woman.
Solution a. P(L′)=P(S)
b. P(M OR S)
c. P(W AND L)
d. P(M|L)
e. P(L|M)
f. P(S|W)
g. P(W|L)
h. P(W OR L)
i. P(M AND S)
j. P(W)
Exercise 2. 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 of confetti.
Find P(H).
Solution
2
October 28, 2025
,OpenStax Introductory Business Statistics 2e
Instructor Answer and Solution Guide
Chapter 3: Probability Topics
Exercise 3. 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 of confetti.
Find P(N).
Solution
P(N) =
Exercise 4. 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 of confetti.
Find P(F).
Solution
P(F) =
Exercise 5. 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 of confetti.
Find P(C).
Solution
P(C) =
Exercise 6. 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 getting a purple jelly bean.
3
October 28, 2025
, OpenStax Introductory Business Statistics 2e
Instructor Answer Guide
Let R = the event of getting a red jelly bean.
Let Y = the event of getting a yellow jelly bean.
Find P(B).
Solution
P(B) =
Exercise 7. 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 getting a purple jelly bean.
Let R = the event of getting a red jelly bean.
Let Y = the event of getting a yellow jelly bean.
Find P(G).
Solution
P(G) =
Exercise 8. 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 getting a purple jelly bean.
Let R = the event of getting a red jelly bean.
Let Y = the event of getting a yellow jelly bean.
Find P(P).
Solution
P(P) =
Exercise 9. 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 getting a purple jelly bean.
Let R = the event of getting a red jelly bean.
4
October 28, 2025
