Question 1

All airline passengers must pass through security screenings, but some are subjected to
additional searches as well. Some travelers who carry laptops wonder if that makes them
more likely to be searched. Data for 420 passengers aboard a cross-country flight are
summarized in the table shown. Does it appear that being subjected to an additional search
is independent of carrying a laptop computer? Explain.

Accepted Answer

The answer of All airline passengers must pass through security...

Question 2

A manufacturing firm orders computer chips from three different companies: 10% from
Company A; 20% from Company B; and 70% from Company C. Some of the computer
chips that are ordered are defective: 4% of chips from Company A are defective; 2% of
chips from Company B are defective; and 0.5% of chips from Company C are defective. A
worker at the manufacturing firm discovers that a randomly selected computer chip is
defective. What is the probability that the computer chip came from Company B? Show
your work.

Accepted Answer

The answer of A manufacturing firm orders computer chips from...

Question 3

Many school administrators watch enrollment numbers for answers to questions parents
ask. Some parents wondered if preferring a particular science course is related to the
student's preference in foreign language. Students were surveyed to establish their
preference in science and foreign language courses. Does it appear that preferences in
science and foreign language are independent? Explain.

Accepted Answer

The answer of Many school administrators watch enrollment numbers for...

Question 4

As you wait your turn in line there are three gold winners in a row. A lively discussion
ensues between the next two customers. One thinks that streak about kills her chances of
winning free merchandise, as the wheel won't come up gold again for a very long time.
The other says that the wheel is clearly on a hot streak, so they are lucky to be next in line.
Comment on their opinions.

Accepted Answer

The answer of As you wait your turn in line...

Question 5

What are the chances that if the monkeys jump every day for a week that at least one will
fall off of the bed?

Accepted Answer

The answer of What are the chances that if the...

Question 6

For purposes of making budget plans for staffing, a college reviewed student's year in
school and area of study. Of the students, 22.5% are seniors, 25% are juniors, 25% are
sophomores, and the rest are freshmen. Also, 40% of the seniors major in the area of
humanities, as did 39% of the juniors, 40% of the sophomores, and 36% of the freshmen.
What is the probability that a randomly selected humanities major is a junior? Show your
work.

Accepted Answer

The answer of For purposes of making budget plans for...

Question 7

A survey of local car dealers revealed that 64% of all cars sold last month had CD players,
28% had alarm systems, and 22% had both CD players and alarm systems.
a. What is the probability one of these cars selected at random had neither a CD player nor
an alarm system?
b. What is the probability that a car had a CD player unprotected by an alarm system?
c. What is the probability a car with an alarm system had a CD player?
d. Are having a CD player and an alarm system disjoint events? Explain.

Accepted Answer

The answer of A survey of local car dealers revealed...

Question 8

For purposes of making on-campus housing assignments, a college classifies its students
as Priority A (seniors), Priority B (juniors), and Priority C (freshmen and sophomores). Of
the students who choose to live on campus, 10% are seniors, 20% are juniors, and the rest
are underclassmen. The most desirable dorm is the newly constructed Gold dorm, and 60%
of the seniors elect to live there. 15% of the juniors also live there, along with only 5% of the
freshmen and sophomores. What is the probability that a randomly selected resident of the
Gold dorm is a senior? Show your work clearly on the back of this page.

Accepted Answer

The answer of For purposes of making on-campus housing assignments,...

Question 9

The monkeys manage to go a whole week without someone bumping their head. One of
the kangaroos insists that they are due for an injury. Another says they must be getting
better at their jumping skills. Do you think they're due for a crash?

Accepted Answer

The answer of The monkeys manage to go a whole...

Question 10

What are the chances that a monkey and a kangaroo will fall off the bed?

Accepted Answer

The answer of What are the chances that a monkey...

Question 11

What are the chances that a monkey will not fall off the bed?

Accepted Answer

The answer of What are the chances that a monkey...

Question 12

According to the American Pet Products Manufacturers Association (APPMA) 2003- 2004
National Pet Owners Survey, 39% of U.S. households own at least one dog and 34% of U.S. households own at least one cat. Assume that 60% of U.S. households own a cat or a dog.
a. What is the probability that a randomly selected U.S. household owns neither a cat nor a
dog?
b. What is the probability that a randomly selected U.S. household owns both a cat and a
dog?
c. What is the probability that a randomly selected U.S. household owns a cat if the
household has a dog?

Accepted Answer

The answer of According to the American Pet Products Manufacturers...

Question 13

A survey of an introductory statistics class in Autumn 2003 asked students whether or not
they ate breakfast the morning of the survey. Results are as follows:  
a. What is the probability that a randomly selected student is female?
b. What is the probability that a randomly selected student ate breakfast?
c. What is the probability that a randomly selected student is a female who ate breakfast?
d. What is the probability that a randomly selected student is female, given that the student
ate breakfast?
e. What is the probability that a randomly selected student ate breakfast, given that the
student is female?
f. Does it appear that whether or not a student ate breakfast is independent of the student's
sex? Explain.

Accepted Answer

The answer of A survey of an introductory statistics class...

Question 14

What is the probability that there is at least one gold winner among the first six customers?

Accepted Answer

The answer of What is the probability that there is...

Question 15

What are the chances that the kangaroos can jump two nights in a row with no one falling
off the bed?

Accepted Answer

The answer of What are the chances that the kangaroos...

Question 16

A survey of families revealed that 58% of all families eat turkey at holiday meals, 44% eat
ham, and 16% have both turkey and ham to eat at holiday meals.
a. What is the probability that a family selected at random had neither turkey nor ham at
their holiday meal?
b. What is the probability that a family selected at random had only ham without having
turkey at their holiday meal?
c. What is the probability that a randomly selected family having turkey had ham at their
holiday meal?
d. Are having turkey and having ham disjoint events? Explain.

Accepted Answer

The answer of A survey of families revealed that 58%...

Question 17

What is the probability that the first gold winner (100%) is the fifth customer in line?

Accepted Answer

The answer of What is the probability that the first...

Question 18

What is the probability that none of the first four customers gets a discount over 20%?

Accepted Answer

The answer of What is the probability that none of...

Question 19

What are the chances that the kangaroos can get away with jumping on the bed for 4
straight nights until they finally have someone fall off the bed on the 5th night?

Accepted Answer

The answer of What are the chances that the kangaroos...

Question 20

If the monkeys enjoy this activity every night for an entire week, what are the chances that
a monkey falls off the bed every one of the seven nights?

Accepted Answer

The answer of If the monkeys enjoy this activity every...

Quiz 8: Regression, Associations, and Predictive Modeling

What are the chances that if the monkeys jump every day for a week that at least one will fall off of the bed?

The monkeys manage to go a whole week without someone bumping their head. One of the kangaroos insists that they are due for an injury. Another says they must be getting better at their jumping skills. Do you think they're due for a crash?

What are the chances that a monkey and a kangaroo will fall off the bed?

What are the chances that a monkey will not fall off the bed?

What is the probability that there is at least one gold winner among the first six customers?

What are the chances that the kangaroos can jump two nights in a row with no one falling off the bed?

What is the probability that the first gold winner (100%) is the fifth customer in line?

What is the probability that none of the first four customers gets a discount over 20%?

What are the chances that the kangaroos can get away with jumping on the bed for 4 straight nights until they finally have someone fall off the bed on the 5th night?

If the monkeys enjoy this activity every night for an entire week, what are the chances that a monkey falls off the bed every one of the seven nights?