Question 1

Doors When trying to reduce energy costs for a home, one strategy is to install high quality
doors. A consumer service wants to test two brands (A and
B) of doors to see which is more
effective at preventing loss of heat. They have four doors of each brand they will install in a
small cabin built for this purpose. The cabin has places for four doors on the north wall and
four on the south wall. The inside of the cabin will be heated, and monitors will be placed
outside each door to measure the amount of heat loss.
  
a. Use the random numbers given to decide which doors to to put in which position.
Explain your method clearly.
  
b. Briefly explain why your assignment strategy is important in helping the manager assess
the effectiveness of the doors.

Accepted Answer

The answer of Doors When trying to reduce energy costs...

Question 2

Consider the following part of a data set: $$\begin{array} { | c | c | c | c | c | c | c | c | } 
\hline \begin{array} { c } 
\text { Age } \
\text { (years) }
\end{array} & \text { Sex } & \text { Only child? } & \begin{array} { c } 
\text { Height } \
\text { (inches) }
\end{array} & \begin{array} { c } 
\text { Weight } \
\text { (pounds) }
\end{array} & \begin{array} { c } 
\text { Credit } \
\text { Hours }
\end{array} & \text { GPA } & \text { Major } \
\hline 21 & \text { Female } & \text { Yes } & 67.00 & 140.0 & 16 & 3.60 & \text { animal science } \
\hline 20 & \text { Female } & \text { No } & 62.00 & 130.0 & 18 & 3.86 & \text { biology } \
\hline 28 & \text { Female } & \text { No } & 64.00 & 188.0 & 21 & 3.25 & \text { psychology } \
\hline 21 & \text { Male } & \text { No } & 65.00 & 140.0 & 15 & 2.95 & \text { psychology } \
\hline 24 & \text { Female } & \text { No } & 67.00 & 130.0 & 20 & 3.00 & \text { anthropology } \
\hline 22 & \text { Male } & \text { Yes } & 68.00 & 135.0 & 15 & 2.94 & \text { journalism } \
\hline
\end{array}$$ 
List the variables in the data set. Indicate whether each variable is treated as categorical or
quantitative in this data set. If the variable is quantitative, state the units.

Accepted Answer

The answer of Consider the following part of a data...

Question 3

Survey. A local news station wants to know what percentage of people favor investing in
new public light-rail system for the city. They conduct a survey, calling homes between
10:00 a.m. and 3:00 p.m. Explain why this sampling plan is biased.

Accepted Answer

The answer of Survey. A local news station wants to...

Question 4

Do you think that milk consumption by young girls is independent of the nationwide
survey year? Use statistics to justify your reasoning.

Accepted Answer

The answer of Do you think that milk consumption by...

Question 5

In order to see which variety of apple tree produces more fruit, a farmer sets up an experiment. He
Has three plots of land with different soil and natural water availability. Each plot has room for
Eight trees. The farmer randomly selects four locations in each plot for the first variety of tree and
The other four get the second variety. This experiment is…
A) randomized block, blocked by variety of tree
B) randomized block, blocked by plot of land
C) completely randomized with one factor: the variety of tree
D) completely randomized with two factors
E) completely randomized with one factor: the plot of land

Accepted Answer

The experiment is a randomized block design, blocked by plot of land, as the farmer uses different plots with varying conditions and randomly assigns tree varieties within each plot.

Question 6

SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
Solve the problem.
-One of the reasons that the Monitoring the Future (MTF) project was started was "to study
changes in the beliefs, attitudes, and behavior of young people in the United States." Data
are collected from 8th, 10th, and 12th graders each year. To get a representative nationwide
sample, surveys are given to a randomly selected group of students. In Spring 2004,
students were asked about alcohol, illegal drug, and cigarette use. Describe the W's, if the
information is given. If the information is not given, state that it is not specified.
• Who:
• What:
• When:
• Where:
• How:
• Why:

Accepted Answer

The answer of SHORT ANSWER. Write the word or phrase...

Question 7

Identify the variables and tell whether each is categorical or quantitative.

Accepted Answer

The answer of Identify the variables and tell whether each...

Question 8

Find the following:
a. What percent of the young girls reported that they drink milk?
b. What percent of the young girls were in the 1989-1991 survey?
c. What percent of the young girls who reported that they drink milk were in the 1989-1991
survey?
d. What percent of the young girls in 1989-1991 reported they drink milk?

Accepted Answer

The answer of Find the following:
a. What percent of the...

Question 9

List the variables. Indicate whether each variable is categorical or quantitative. If the
variable is quantitative, tell the units.

Accepted Answer

The answer of List the variables. Indicate whether each variable...

Question 10

List the variables. Indicate whether each variable is categorical or quantitative. If the
variable is quantitative, tell the units.

Accepted Answer

The answer of List the variables. Indicate whether each variable...

Question 11

Announcements. A high school in Wisconsin stopped having announcements read to
students over the intercom system, choosing to have announcements displayed on
television monitors located throughout the building. To see how students feel about the
new system the principal wants to conduct a survey. Explain how to select a sample of
about 500 students using each sampling method below:
a. Simple random sample
b. Stratified random sample with grade levels as strata
c. Cluster sample with classrooms as clusters

Accepted Answer

The answer of Announcements. A high school in Wisconsin stopped...

Question 12

UFOs. A National Geographic survey in 2012 found that 36% of Americans believe in
aliens. (The outer-space kind, not visitors from foreign countries!) If you were to randomly
select 10 Americans, what is the average number of believers you'd expect in your sample?
Conduct a simulation to find out!
a. Explain how you will use the random numbers listed below to conduct your simulation.
b. Carefully label your simulation for 2 trials.  
c. State your conclusion.

Accepted Answer

The answer of UFOs. A National Geographic survey in 2012...

Question 13

What is the marginal distribution of milk consumption?

Accepted Answer

The answer of What is the marginal distribution of milk...

Question 14

Gun control Two friends who strongly disagree on whether there should be stricter
regulation of guns in this country want to conduct a poll of the students in their school to
see which side most students agree with. Each came back with a different version of the
question they want to ask.
Version 1: Do you think the government should respect our 2nd Amendment rights and allow
lawabiding citizens to own guns?
Version 2: In the wake of recent mass shootings, should laws be passed to keep guns out of the
hands of people with a history of violence?
a. Which version would make it seem like people oppose stricter gun regulation? What
kind of bias is this?
b. Is the version you did not pick in part a less biased?
c. Is it reasonable for a person to respond 'yes' to both questions?

Accepted Answer

The answer of Gun control Two friends who strongly disagree...

Question 15

List the variables. Indicate whether each variable is categorical or quantitative. If the
variable is quantitative, tell the units.

Accepted Answer

The answer of List the variables. Indicate whether each variable...

Question 16

Political math A recent study by Yale professors found that people's ability to do
mathematics computations got worse when the result went against the person's political
ideology. This was based on a randomized experiment in which people were given the
same basic computation, but some were given the question in a politically neutral context
and others were given the same computation in a context in which the correct answer went
against their political ideology. The difference between the proportion of people who got
the question wrong in a 'neutral' context and those who got the question wrong in a
'political' context was reported to be "statistically significant."
a. Briefly explain what "statistically significant" means in this context.
b. Would it be appropriate for the news media to report that the political context caused the
poor computational results? Explain.

Accepted Answer

The answer of Political math A recent study by Yale...

Question 17

Describe the W's, if the information is given:
• Who:
• What:
• When:
• Where:
• How:
• Why:

Accepted Answer

The answer of Describe the W's, if the information is...

Question 18

Describe the W's, if the information is given:
• Who:
• What:
• When:
• Where:
• How:
• Why:

Accepted Answer

The answer of Describe the W's, if the information is...

Question 19

Describe the W's, if the information is given:
• Who:
• What:
• When:
• Where:
• How:
• Why:

Accepted Answer

The answer of Describe the W's, if the information is...

Question 20

Consider the following pie charts of the a subset of the data above:  
Do the pie charts above indicate that milk consumption by young girls is independent of
the nationwide survey year? Explain.

Accepted Answer

The answer of Consider the following pie charts of the...

Quiz 8: Regression, Associations, and Predictive Modeling

Survey. A local news station wants to know what percentage of people favor investing in new public light-rail system for the city. They conduct a survey, calling homes between 10:00 a.m. and 3:00 p.m. Explain why this sampling plan is biased.

Do you think that milk consumption by young girls is independent of the nationwide survey year? Use statistics to justify your reasoning.

Identify the variables and tell whether each is categorical or quantitative.

List the variables. Indicate whether each variable is categorical or quantitative. If the variable is quantitative, tell the units.

List the variables. Indicate whether each variable is categorical or quantitative. If the variable is quantitative, tell the units.

What is the marginal distribution of milk consumption?

List the variables. Indicate whether each variable is categorical or quantitative. If the variable is quantitative, tell the units.

Describe the W's, if the information is given: • Who: • What: • When: • Where: • How: • Why:

Describe the W's, if the information is given: • Who: • What: • When: • Where: • How: • Why:

Describe the W's, if the information is given: • Who: • What: • When: • Where: • How: • Why:

Consider the following pie charts of the a subset of the data above: Do the pie charts above indicate that milk consumption by young girls is independent of the nationwide survey year? Explain.