Question 1

Use the following to answer the questions below:
The USStates dataset, used throughout the textbook, contains information on the 50 U.S. states. A small segment from the dataset is displayed in the following table.
 
-What variable was used to determine that 42.7% of Connecticut state residents have a college degree? Is it categorical or quantitative?

Accepted Answer

The variable "whether or not they have a college degree" is categorical because it classifies individuals into categories (those with a degree and those without).

Question 2

Use the following to answer the questions below:
The USStates dataset, used throughout the textbook, contains information on the 50 U.S. states. A small segment from the dataset is displayed in the following table.
 
-The ________ variable is used to understand or predict values of the ________ variable.

Accepted Answer

The explanatory variable is used to understand or predict the values of the response variable.

Question 3

Sampling from a Population
-A population includes all individuals or objects of interest.

Accepted Answer

A population is defined as the entire group of individuals or instances about whom we hope to learn or draw conclusions.

Question 4

Sampling from a Population
-A population is a subset of the sample.

Accepted Answer

A sample is a subset of a population, not the other way around. A population includes all members of a defined group, while a sample consists of some members selected from that group.

Question 5

Sampling from a Population
-A biased sample is one that does not accurately reflect or represent the population.

Accepted Answer

A biased sample is one that systematically overrepresents or underrepresents certain segments of the population, leading to inaccurate conclusions about the population as a whole.

Question 6

Use the following to answer the questions below:
State whether the data are best described as a population or a sample.
-The makers of M&M's state that when they package their candies they thoroughly mix the colored candies together and randomly put them into packages. A student purchases a bag of Milk Chocolate M&M's from the vending machine.

Accepted Answer

The bag of M&M's purchased by the student is a sample because it represents a subset of all possible M&M's packages produced by the manufacturer.

Question 7

Use the following to answer the questions below:
State whether the data are best described as a population or a sample.
-A professor wants to schedule a review session for an exam. He asks all students enrolled in the course their preferred time, and they all respond.

Accepted Answer

Population - he collects data from everyone enrolled in the course

Question 8

Use the following to answer the questions below:
State whether the data are best described as a population or a sample.
-A researcher has identified a beach with a substantial number of driftwood logs. She randomly chooses 30 logs and takes core samples from those logs.

Accepted Answer

Sample. She has only measured a subset of all of the logs on the beach.

Question 9

Use the following to answer the questions below:
State whether the data are best described as a population or a sample.
-A football fan recorded the number of rushing yards for all NFL running backs who played last season.

Accepted Answer

Population. The data were collected on all of the running backs.

Question 10

Use the following to answer the questions below:
A tree enthusiast is interested in estimating the typical length of oak tree leaves. He chooses 30 leaves from the oak tree in his backyard.
-What is the sample in this situation?

Accepted Answer

The answer of Use the following to answer the questions...

Question 11

Use the following to answer the questions below:
A tree enthusiast is interested in estimating the typical length of oak tree leaves. He chooses 30 leaves from the oak tree in his backyard.
-What is the population in which the tree enthusiast is interested?

Accepted Answer

The answer of Use the following to answer the questions...

Question 12

Use the following to answer the questions below:
A tree enthusiast is interested in estimating the typical length of oak tree leaves. He chooses 30 leaves from the oak tree in his backyard.
-Is this a biased sampling strategy?

Accepted Answer

This is a biased sampling strategy as he is only taking the leaves from one tree; there could be something unusual about that tree. At best we can generalize to the leaves on the tree in his backyard.

Question 13

In each situation, indicate whether the method of data collection is biased.
-Ask the students at the gym on a Tuesday afternoon how many hours a week they work out to estimate the average amount of time students at the university work out.

Accepted Answer

Biased, because only students at the gym (who are likely working out) were sampled. Students who don't go to the gym (and thus possibly don't work out) were not included in the sample. Another potential source of bias is that, for various reasons, the students asked the question may exaggerate about the amount of time they work out each week.

Question 14

In each situation, indicate whether the method of data collection is biased.
-A professor asks her class of first year students if any of them consumed alcohol over the weekend.

Accepted Answer

This sample is likely biased. First year students would tend to be under the age of 21, and thus it would be illegal for them to be consuming alcohol. They might not want to truthfully tell their professor about engaging in an illegal behavior.

Question 15

In each situation, indicate whether the method of data collection is biased.
-A campus bookstore is holding a drawing to give away five free textbooks (one per student). Students enter the contest by writing their name and contact information on an index card. The index cards were placed in a bowl, thoroughly mixed around, and five cards were selected. Those five students were contacted and received their free textbook.

Accepted Answer

This is a non-biased sample of the students who entered the contest (the population in this situation is the student who entered the contest).

Question 16

In each situation, indicate whether the method of data collection is biased.
-A professor is considering a new textbook for her introductory statistics class. She wants to choose a book that emphasizes graphing data. A book that she is considering has 530 pages. To estimate the proportion of pages in the book that have displays of data, she randomly generates 20 numbers between 1 and 530. She then records whether or not each selected page contains displays of data.

Accepted Answer

Her pages were selected by generating random numbers. This is an unbiased sampling method.

Question 17

In each situation, indicate whether the method of data collection is biased.
-A reporter from the campus newspaper is writing an article about student opinions on Greek organizations (sororities and fraternities). For his article, he visits all of the Greek houses on campus and interviews a random sample of residents of each house.

Accepted Answer

His sample only contains individuals who have chosen to participate in Greek life, and this the opinions will be biased towards the individuals who choose to belong to a Greek organization.

Question 18

Use the following to answer the questions below:
A group of researchers investigated the effect of media usage (whether or not subjects watch television or use the Internet) in the bedroom on "Tiredness" during the day (measured on a 50 point scale).
-Identify the variables described and whether they are categorical or quantitative.

Accepted Answer

Media usage in the bedroom is categorical as it involves categories (watching TV or using the Internet). "Tiredness" is quantitative as it is measured on a numerical scale.

Question 19

Use the following to answer the questions below:
A group of researchers investigated the effect of media usage (whether or not subjects watch television or use the Internet) in the bedroom on "Tiredness" during the day (measured on a 50 point scale).
-Identify the variables as either explanatory or response variables.

Accepted Answer

Media usage in the bedroom is the explanatory variable as it is being investigated for its effect on "Tiredness," which is the response variable being measured.

Question 20

Use the following to answer the questions below:
A group of researchers investigated the effect of media usage (whether or not subjects watch television or use the Internet) in the bedroom on "Tiredness" during the day (measured on a 50 point scale).
-To collect these data, the researchers randomly selected homes to visit and interviewed the adult member of the household whose birthday was nearest. Is this an experiment or an observational study?

Accepted Answer

This is an observational study because treatments are not being applied to the study participants; they are being asked about their normal behaviors.

Quiz 1: Collecting Data

Use the following to answer the questions below: The USStates dataset, used throughout the textbook, contains information on the 50 U.S. states. A small segment from the dataset is displayed in the following table. -The variable is used to understand or predict values of the variable.

Sampling from a Population -A population includes all individuals or objects of interest.

Sampling from a Population -A population is a subset of the sample.

Sampling from a Population -A biased sample is one that does not accurately reflect or represent the population.

Use the following to answer the questions below: State whether the data are best described as a population or a sample. -A professor wants to schedule a review session for an exam. He asks all students enrolled in the course their preferred time, and they all respond.

Use the following to answer the questions below: State whether the data are best described as a population or a sample. -A researcher has identified a beach with a substantial number of driftwood logs. She randomly chooses 30 logs and takes core samples from those logs.

Use the following to answer the questions below: State whether the data are best described as a population or a sample. -A football fan recorded the number of rushing yards for all NFL running backs who played last season.

Use the following to answer the questions below: A tree enthusiast is interested in estimating the typical length of oak tree leaves. He chooses 30 leaves from the oak tree in his backyard. -What is the sample in this situation?

Use the following to answer the questions below: A tree enthusiast is interested in estimating the typical length of oak tree leaves. He chooses 30 leaves from the oak tree in his backyard. -What is the population in which the tree enthusiast is interested?

Use the following to answer the questions below: A tree enthusiast is interested in estimating the typical length of oak tree leaves. He chooses 30 leaves from the oak tree in his backyard. -Is this a biased sampling strategy?

In each situation, indicate whether the method of data collection is biased. -Ask the students at the gym on a Tuesday afternoon how many hours a week they work out to estimate the average amount of time students at the university work out.

In each situation, indicate whether the method of data collection is biased. -A professor asks her class of first year students if any of them consumed alcohol over the weekend.