Question 1

College students' spending A consumer group wants to see if a new education program
will improve the spending habits of college students. Students in an economics class are
randomly assigned to three different courses on spending habits.
a. What are the experimental units?
b. How many factors are there?
c. How many treatments are there?
d. What is the response variable?

Accepted Answer

The answer of College students' spending A consumer group wants...

Question 2

Placebos are a tool for
A) sampling
B) randomization
C) blocking
D) blinding
E) control

Accepted Answer

Placebos are used in experiments to blind participants to the treatment they are receiving, helping to prevent bias in the results.

Question 3

A chemistry professor who teaches a large lecture class surveys his students who attend his class
About how he can make the class more interesting, hoping he can get more students to attend. This
Survey method suffers from
A) nonresponse bias
B) none of these
C) response bias
D) voluntary response bias
E) undercoverage

Accepted Answer

The answer of A chemistry professor who teaches a large...

Question 4

A researcher wants to compare the effect of a new type of shampoo on hair condition. The
Researcher believes that men and women may react to the shampoo differently. Additionally, the
Researcher believes that the shampoo will react differently on hair that is dyed. The subjects are
Split into four groups: men who dye their hair; men who do not dye their hair; women who dye
Their hair; women who do not dye their hair. Subjects in each group are randomly assigned to the
New shampoo and the old shampoo. This experiment
A) has three factors (shampoo type, gender, whether hair is dyed).
B) has two factors (gender and whether hair is dyed) blocked by shampoo type.
C) is completely randomized.
D) has two factors (shampoo type and whether hair is dyed) blocked by gender
E) has one factor (shampoo type), blocked by gender and whether hair is dyed.

Accepted Answer

The answer of A researcher wants to compare the effect...

Question 5

Military funding A college group is investigating student opinions about funding of the
military. They phone a random sample of students at the college, asking each person one of
these questions (randomly chosen):
A: "Do you think that funding of the military should be increased so that the United States can
better protect its citizens?"
B: "Do you think that funding of the military should be increased?"
Which question do you expect will elicit greater support for increased military funding?
Explain. What kind of bias is this?

Accepted Answer

The answer of Military funding A college group is investigating...

Question 6

Would it make sense to have a control group that did not get any of the treatments
described above?

Accepted Answer

The answer of Would it make sense to have a...

Question 7

Describe an advantage to random assignment of treatment.

Accepted Answer

The answer of Describe an advantage to random assignment of...

Question 8

Someone suggested that Max arrange the tanks so that six with the lowest temperature are
on one end of the room, and the six with the highest temperature are at the other end of the
room. Explain how this could introduce confounding into the experiment.

Accepted Answer

The answer of Someone suggested that Max arrange the tanks...

Question 9

Double-blinding in experiments is important so that
I. The evaluators do not know which treatment group the participants are in.
II. The participants do not know which treatment group they are in.
III. No one knows which treatment any of the participants is getting.
A) I only
B) III only
C) II only
D) I, II, and III
E) I and II

Accepted Answer

Double-blinding ensures that both the evaluators and the participants are unaware of the treatment assignments, reducing bias and placebo effects.

Question 10

Which of the following is not required in an experimental design?
A) replication
B) control
C) All of these are required in an experimental design.
D) randomization
E) blocking

Accepted Answer

The answer of Which of the following is not required...

Question 11

Among a dozen eggs, three are rotten. A cookie recipe calls for two eggs; they'll be selected
Randomly from that dozen. Which plan could be used to simulate the number of rotten eggs that
Might be chosen?
I. Let 0, 1, and 2 represent the rotten eggs, and 3, 4, …, 11 the good eggs. Generate two random
Numbers 0-11, ignoring repeats.
II. Randomly generate a 0, 1, or 2 to represent the number of rotten eggs you get.
III. Since 25% of the eggs are rotten, let 0 = rotten and 1, 2, 3 = good. Generate two random numbers
0-3 and see how may 0's you get.
A) I and III
B) I only
C) I, II, and III
D) II only
E) III only

Accepted Answer

Plan I correctly simulates the selection of two eggs from a dozen, accounting for the specific rotten and good eggs. Plan III incorrectly represents the probability distribution, and Plan II does not simulate the selection process accurately.

Question 12

The January 2005 Gallup Youth Survey telephoned a random sample of 1,028 U.S. teens and asked
These teens to name their favorite movie from 2004. Napoleon Dynamite had the highest percentage
With 8% of teens ranking it as their favorite movie. Which is true?
I. The population of interest is all U.S. teens.
II. 8% is a statistic and not the actual percentage of all U.S. teens who would rank this movie as
Their favorite.
III. This sampling design should provide a reasonably accurate estimate of the actual percentage of
All U.S. teens who would rank this movie as their favorite.
A) III only
B) I, II, and III
C) II only
D) I and II
E) I only

Accepted Answer

The population of interest is indeed all U.S. teens (I). The 8% is a statistic because it is derived from a sample, not the entire population (II). A random sample of 1,028 teens should provide a reasonably accurate estimate of the actual percentage (III).

Question 13

More dogs are being diagnosed with thyroid problems than have been diagnosed in the past. A
Researcher identified 50 puppies without thyroid problems and kept records of their diets for
Several years to see if any developed thyroid problems. This is a(n)
A) survey
B) retrospective study
C) randomized experiment
D) blocked experiment
E) prospective study

Accepted Answer

The study involves observing the puppies over time to see if they develop thyroid problems, which is characteristic of a prospective study.

Question 14

Suppose a school district decides to randomly test high school students for attention deficit
Disorder (ADD). There are three high schools in the district, each with grades 9-12. The school
Board pools all of the students together and randomly samples 250 students. Is this a simple
Random sample?
A) No, because we can't guarantee that students from each school in the sample.
B) No, because we can't guarantee that students from each grade in the sample.
C) Yes, because the students were chosen at random.
D) Yes, because they could have chosen any 250 students from the district.
E) Yes, because each student is equally likely to be chosen.

Accepted Answer

The answer of Suppose a school district decides to randomly...

Question 15

A basketball player has a 70% free throw percentage. Which plan could be used to simulate the
Number of free throws she will make in her next five free throw attempts?
I. Let 0,1 represent making the first shot, 2, 3 represent making the second shot,…, 8, 9 represent
Making the fifth shot. Generate five random numbers 0-9, ignoring repeats.
II. Let 0, 1, 2 represent missing a shot and 3, 4,…, 9 represent making a shot. Generate five random
Numbers 0-9 and count how many numbers are in 3-9.
III. Let 0, 1, 2 represent missing a shot and 3, 4,…, 9 represent making a shot. Generate five random
Numbers 0-9 and count how many numbers are in 3-9, ignoring repeats.
A) II only
B) III only
C) II and III
D) I, II, and III
E) I only

Accepted Answer

Plan II correctly simulates the 70% chance of making a shot by assigning 7 out of 10 numbers (3-9) to making a shot. Plan III incorrectly ignores repeats, which is not necessary in this context. Plan I does not correctly simulate the probability distribution.

Question 16

Explain how replication would be used in this study.

Accepted Answer

The answer of Explain how replication would be used in...

Question 17

Video games A headline in a local newspaper announced "Video game playing can lead to
better spatial reasoning abilities." The article reported that a study found "statistically
significant differences" between teens who play video games and teens who do not, with
teens who play video games testing better in spatial reasoning. Do you think the headline
was appropriate? Explain.

Accepted Answer

The answer of Video games A headline in a local...

Question 18

Good CDs Brian is a systems manager for a large company. In his work, he has found that
about 5% of all CDs he orders are bad. He needs to give one of the executives at his
company five good CDs. Conduct a simulation to estimate how many CDs Brian will have
to check to get five good CDs for the executive.
a. Describe how you will use a random number table to conduct this simulation.
b. Show three trials by clearly labeling the random number table given below. Specify the
outcome for each trial. $$\begin{array} { | c | c | c | } 
\hline \text { Trial } & \text { Simulation } & \text { Outcome } \
\hline \# 1 & 03242506921897728370 & \
\hline \# 2 & 78695214028552581183 & \
\hline \# 3 & 60809067653999681915 & \
\hline
\end{array}$$ 
c. State your conclusion.

Accepted Answer

The answer of Good CDs Brian is a systems manager...

Question 19

A company sponsoring a new Internet search engine wants to collect data on the ease of using it.
Which is the best way to collect the data?
A) census
B) simulation
C) observational study
D) experiment
E) sample survey

Accepted Answer

A sample survey is the best way to collect data on user experience, as it allows the company to gather feedback from a representative group of users about their ease of using the search engine.

Question 20

Bone Builder Researchers believe that a new drug called Bone Builder will help bones heal
after children have broken or fractured a bone. The researchers believe that Bone Builder
will work differently on bone breaks than on bone fractures, because of differences in
initial bone condition. Bone Builder will be used in conjunction with traditional casts. To
test the impact of Bone Builder on bone healing, the researchers recruit 18 children with
bone breaks and 30 children with bone fractures. Design an appropriate experiment to
determine if Bone Builder will help bones heal.

Accepted Answer

The answer of Bone Builder Researchers believe that a new...

Quiz 8: Regression, Associations, and Predictive Modeling

Placebos are a tool for

A chemistry professor who teaches a large lecture class surveys his students who attend his class About how he can make the class more interesting, hoping he can get more students to attend. This Survey method suffers from

Would it make sense to have a control group that did not get any of the treatments described above?

Describe an advantage to random assignment of treatment.

Someone suggested that Max arrange the tanks so that six with the lowest temperature are on one end of the room, and the six with the highest temperature are at the other end of the room. Explain how this could introduce confounding into the experiment.

Double-blinding in experiments is important so that I. The evaluators do not know which treatment group the participants are in. II. The participants do not know which treatment group they are in. III. No one knows which treatment any of the participants is getting.

Which of the following is not required in an experimental design?

More dogs are being diagnosed with thyroid problems than have been diagnosed in the past. A Researcher identified 50 puppies without thyroid problems and kept records of their diets for Several years to see if any developed thyroid problems. This is a(n)

Suppose a school district decides to randomly test high school students for attention deficit Disorder (ADD) . There are three high schools in the district, each with grades 9-12. The school Board pools all of the students together and randomly samples 250 students. Is this a simple Random sample?

Explain how replication would be used in this study.

A company sponsoring a new Internet search engine wants to collect data on the ease of using it. Which is the best way to collect the data?