Question 1

One manager suggesting just going to the stores in the city where the company is headquartered so they wouldn't have to travel far. What type of sampling would this be? Explain why this method is biased. Be sure to name the kind(s) of bias you describe and link it to the variable of interest.

Accepted Answer

The answer of One manager suggesting just going to the...

Question 2

Max wants to start a farm to grow mussels. He needs to determine the best environment for growing them. He is going to try two different amounts of salt in the water (salinity) and three different water temperatures. For his experiment he has
18 aquariums, each with 20 mussels. He wants to see which environment produces the largest mussels.
-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 Max wants to start a farm to...

Question 3

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

Accepted Answer

Placebos are a tool for blinding, meaning they are used to prevent participants from knowing whether they are receiving the actual treatment or a harmless substitute. This helps eliminate bias in the study and allows researchers to measure the true effects of the treatment.

Question 4

The principal of a small elementary school wants to select a simple random sample of 24 students.
The school has 12 classrooms with 18 students in each class. She decides to randomly select two
Students from each classroom. Is this a simple random sample?
A) Yes, because the students were selected at random.
B) Yes, because a stratified sample is a type of simple random sample.
C) No, because each student did not have an equal chance of being selected.
D) No, because not all combinations of 24 students could have been chosen.
E) Yes, because each student had an equal chance to be selected.

Accepted Answer

The answer of The principal of a small elementary school...

Question 5

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. $$\begin{array} { | c | c c c c c | c | } 
\hline \text { Trial \# } &&&{ \text { The run } } &&& \text { Outcome } \
\hline 1 & 98642 & 20639 & 23185 & 56282 & 69929 & \
\hline 2 & 14125 & 38872 & 94168 & 71622 & 35940 & \
\hline
\end{array}$$ 
c. State your conclusion.

Accepted Answer

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

Question 6

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 one factor (shampoo type), blocked by gender and whether hair is dyed.
B) is completely randomized.
C) has two factors (gender and whether hair is dyed) blocked by shampoo type.
D) has two factors (shampoo type and whether hair is dyed) blocked by gender.
E) has three factors (shampoo type, gender, whether hair is dyed).

Accepted Answer

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

Question 7

Of the following, which is not a critical part of designing a good experiment?
A) Random selection of subjects.
B) Random assignment of subjects to treatments.
C) All of these are important.
D) Replication of a sufficient number of subjects.
E) Control of known sources of variability.

Accepted Answer

Random selection of subjects is not always necessary for a good experiment, especially if the goal is to establish causality rather than generalize to a larger population. Random assignment, replication, and control of variability are more critical for internal validity.

Question 8

Suppose your local 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 there are students from each grade in the sample.
B) No, because we can't guarantee that there are students from each school in the sample.
C) Yes, because the students were chosen at random.
D) Yes, because each student is equally likely to be chosen.
E) Yes, because they could have chosen any 250 students from throughout the district.

Accepted Answer

The answer of Suppose your local school district decides to...

Question 9

Sweet potato pie Sam is preparing sweet potato pies as his dessert for Thanksgiving. The store he shops at sells six sweet potatoes in a bag. He has found that each bag will contain
0, 1, or 2 bad sweet potatoes. Based on experience he estimates that there will be no bad sweet potatoes in 40% of the bags, one bad sweet potato in 30% of the bags, and two bad sweet potatoes in the rest. Conduct a simulation to estimate how many bags Sam will have to purchase to have three dozen sweet good potatoes.
a. Describe how you will use a random number table to conduct this simulation.
b. Show two trials by clearly labeling the random number table given below. Specify the outcome for each trial. $\begin{array}{|c|cc|c|}
\hline \text { Trial } &{\text { Simulation }} && \text { Outcome } \
\hline{\# 1} & 578821 & 76309 & \
\hline & 635508 & 29418 & \
\hline{\# 2} & 133026 & 34993 & \
\hline & 54636 & 17877 & \
\hline
\end{array}$ 
c. State your conclusion.

Accepted Answer

The answer of Sweet potato pie Sam is preparing sweet...

Question 10

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) simulation
B) observational study
C) sample survey
D) census
E) experiment

Accepted Answer

A sample survey would be the best way to collect data on the ease of using the new search engine. This would involve selecting a representative sample of users and asking them to rate the ease of use on a scale. A census would be too time-consuming and costly, an experiment may not be ethical or practical in this case, a simulation may not accurately reflect real-life usage, and an observational study may not provide enough information on the specific aspects of ease of use.

Question 11

Max wants to start a farm to grow mussels. He needs to determine the best environment for growing them. He is going to try two different amounts of salt in the water (salinity) and three different water temperatures. For his experiment he has
18 aquariums, each with 20 mussels. He wants to see which environment produces the largest mussels.
-Identify the subjects.

Accepted Answer

The answer of Max wants to start a farm to...

Question 12

As a 4-H project, Billy is raising chickens. He feeds and waters them every day, and collects the eggs every other day, selling them to people in the neighborhood. He has found that each hen's nest will contain from 0 to 2 eggs. Based on past experience he estimates that there will be no eggs in 10% of the nests, one egg in 30% of the nests, and 2 eggs in the other
60%. Conduct a simulation to estimate how many nests Bill will have to visit to collect a dozen eggs.
-Show three trials by clearly labeling the random number table given below. Specify the outcome for each trial.

$ \begin{array}{llllll}57528 & 78305 & 63508 & 29418\
 90676&31993 & 54636&17877\
31574 &28042 & 72621& 84818 
\end{array}$

Accepted Answer

The answer of As a 4-H project, Billy is raising...

Question 13

Can watching a movie temporarily raise your pulse rate? Researchers have 50 volunteers check their pulse rates. Then they watch an action film, after which they check their pulse rates once more. Which aspect of experimentation is present in this research?
A) randomization
B) blinding
C) none of these
D) a placebo
E) a control group

Accepted Answer

None of these. The given scenario lacks any of the essential components of experimentation such as randomization, blinding, a placebo, or a control group. It is just an observation without any scientific setup.

Question 14

M&Ms The Mars candy company starts a marketing campaign that puts a plastic game piece in each bag of M&Ms. 25% of the pieces show the letter "M", 10% show the symbol "&", and the rest just say "Try again". When you collect a set of three symbols "M", "&", and "M" you can turn them in for a free bag of candy. About how many bags will a consumer have to buy to get a free one? Use 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. $\begin{array}{|c|lllll|l|}
\hline \text { Trial \# } &&&{\text { The run }} &&& \text { Outcome } \
\hline 1 & 69074 & 91976 & 33584 & 94138 & 87637 & \
\hline 2 & 48324 & 77928 & 31249 & 64710 & 02295 & \
\hline
\end{array}$ 
c. State your conclusion.

Accepted Answer

The answer of M&Ms The Mars candy company starts a...

Question 15

Max wants to start a farm to grow mussels. He needs to determine the best environment for growing them. He is going to
try two different amounts of salt in the water (salinity) and three different water temperatures. For his experiment he has
18 aquariums, each with 20 mussels. He wants to see which environment produces the largest mussels.
-Identify the response variable.

Accepted Answer

The answer of Max wants to start a farm to...

Question 16

Grape juice and blood pressure Researchers who wanted to see if drinking grape juice could help people lower their blood pressure got 120 non-smokers to volunteer for a study. They measured each person's blood pressure and then randomly divided the
subjects into two groups. One group drank a glass of grape juice every day while the other
did not. After sixty days the researchers measured everyone's blood pressure again. They reported that differences in changes in blood pressure between the groups were not
statistically significant.
a. Was this an experiment or an observational study? Explain briefly.
b. Briefly explain what "not statistically significant" means in this context.
c. Briefly explain why the researchers randomly assigned the subjects to the groups.
d. Since everyone's blood pressure was measured at the beginning and at the end of the study, the researchers could have simply looked at the grape juice drinkers to see if their blood pressure changed. Briefly explain why the researchers bothered to include the
control group.
e. Briefly explain why the researchers studied only non-smokers.
f. Other researchers now plan to replicate this study using both smokers and non-smokers. Briefly describe the design strategy you think they should use.

Accepted Answer

The answer of Grape juice and blood pressure Researchers who...

Question 17

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 18

A factory has 20 assembly lines producing a popular toy. To inspect a representative sample of 100 toys, quality control staff randomly selected 5 toys from each line's output. Was this a simple random sample?
A) Yes, because the toys were selected at random.
B) Yes, because each toy produced had an equal chance to be selected.
C) No, because toys do not come off the assembly line at random.
D) No, because not all combinations of 100 toys could have been chosen.
E) Yes, because a stratified sample is a type of simple random sample.

Accepted Answer

This is not a simple random sample because by selecting exactly 5 toys from each line, not all combinations of 100 toys had an equal chance of being chosen. A simple random sample requires that every possible sample of the desired size has an equal chance of being selected, which is not the case here.

Question 19

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 20

For a school project, Max must design a survey. For his survey he plans to randomly select families and gather information about all the children in each of those families. He must have at least 20 children in his sample. The number of children per family in the U.S. is given in the table below. How many families should Max expect to survey to reach at least 20 children? (treat “5 or more” as 5.)

$\begin{array}{|l|l|l|l|l|l|l|}
\hline \text {  No. of Children }& 0 & 1 & 2 & 3 & 4 & 5 \text {  or more} \
\hline \%   \text { of families} & 17 & 23 & 25 & 16 & 10 & 9 \
\hline
\end{array}$

-State your conclusion.

Accepted Answer

The answer of For a school project, Max must design...

Quiz 3: Displaying and Describing Categorical Data

One manager suggesting just going to the stores in the city where the company is headquartered so they wouldn't have to travel far. What type of sampling would this be? Explain why this method is biased. Be sure to name the kind(s) of bias you describe and link it to the variable of interest.

Placebos are a tool for

The principal of a small elementary school wants to select a simple random sample of 24 students. The school has 12 classrooms with 18 students in each class. She decides to randomly select two Students from each classroom. Is this a simple random sample?

Of the following, which is not a critical part of designing a good experiment?

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?

Can watching a movie temporarily raise your pulse rate? Researchers have 50 volunteers check their pulse rates. Then they watch an action film, after which they check their pulse rates once more. Which aspect of experimentation is present in this research?

A factory has 20 assembly lines producing a popular toy. To inspect a representative sample of 100 toys, quality control staff randomly selected 5 toys from each line's output. Was this a simple random sample?