Question 1

Legislation Poll
A councillor was interested in determining whether people between the ages of 18 and 30 years of age would react to a piece of legislation differently than people over 30 years of age. The councillor polled a sample of 150 people from his district. The resulting data are shown in the table below:
Reaction 
-Refer to the Legislation Poll table. Construct a pie chart for each of the age groups.

Accepted Answer

The answer of Legislation Poll
A councillor was interested in determining...

Question 2

If the linear relationship between the dependent and independent variables is positive, the scatterplot will show the data points on the (x, y) plane moving generally from the lower left corner to the upper right corner.

Accepted Answer

This is because as the independent variable increases, so does the dependent variable, resulting in a positive correlation.

Question 3

Gender Differences Narrative
Male and female respondents to a questionnaire about gender differences are categorized into three groups according to their answers, as shown below: 
-Refer to Gender Differences Narrative. Create a side-by-side bar chart to describe these data.

Accepted Answer

The answer of Gender Differences Narrative
Male and female respondents to...

Question 4

When constructing a scatterplot, the independent variable x is placed on the horizontal axis, and the dependent variable y is placed on the vertical axis.

Accepted Answer

This is true for constructing a scatterplot.

Question 5

A perfect correlation between two variables will always produce a correlation coefficient of +1.0.

Accepted Answer

A perfect correlation between two variables can produce a correlation coefficient of +1.0 for a perfect positive correlation or -1.0 for a perfect negative correlation.

Question 6

Gender Differences Narrative
Male and female respondents to a questionnaire about gender differences are categorized into three groups according to their answers, as shown below: 
-Refer to Gender Differences Narrative. Which of the charts created in the above three questions best depicts the difference or similarity of the responses of men and women? Give reasons for your answer.

Accepted Answer

The answer of Gender Differences Narrative
Male and female respondents to...

Question 7

Students' GPA Narrative
A law school administrator was interested in whether a student's score on the entrance exam can be used to predict a student's grade point average (GPA) after one year of law school. The administrator took a random sample of 15 students and computed the following summary information, where x = entrance exam score and y = GPA after one year:      and  .
-Refer to Students' GPA Narrative. Interpret the correlation coefficient found in the previous question as to whether it could be used to predict students' GPAs after the first year. Justify your answer.

Accepted Answer

The answer of Students' GPA Narrative
A law school administrator was...

Question 8

Selling Price and Age of Home Narrative
A real estate agent is interested in knowing whether there is a relationship between the age of a house and the selling price. Listed below are the ages (in years) and selling prices (in $1000s) of a sample of six houses the agent has sold in the past year: 
-Refer to Selling Price and Age of Home Narrative. Based on the plot in the previous question, does there appear to be a relationship between the age of a house and selling price?

Accepted Answer

The answer of Selling Price and Age of Home Narrative
A...

Question 9

The scatterplot is a graph that is used to represent the relationship between two quantitative variables.

Accepted Answer

The scatterplot is indeed used to represent the relationship between two quantitative variables through the use of dots or points plotted on a two-dimensional graph.

Question 10

The best-fitting line relating the dependent variable y to the independent variable x, often called the regression or least-squares line, is found by minimizing the sum of the squared differences between the data points and the line itself.

Accepted Answer

This statement is true. The regression or least-squares line is a line that best fits the data points by minimizing the sum of the squared differences between the data points and the line.

Question 11

Legislation Poll
A councillor was interested in determining whether people between the ages of 18 and 30 years of age would react to a piece of legislation differently than people over 30 years of age. The councillor polled a sample of 150 people from his district. The resulting data are shown in the table below:
Reaction 
-Refer to the Legislation Poll table. Construct a side-by-side bar chart.

Accepted Answer

The answer of Legislation Poll
A councillor was interested in determining...

Question 12

Legislation Poll
A councillor was interested in determining whether people between the ages of 18 and 30 years of age would react to a piece of legislation differently than people over 30 years of age. The councillor polled a sample of 150 people from his district. The resulting data are shown in the table below:
Reaction 
-Refer to the Legislation Poll table. Which of the two types of presentations in the previous two questions is more easily understood?

Accepted Answer

The answer of Legislation Poll
A councillor was interested in determining...

Question 13

A scatterplot is particularly useful in determining if the relationship between the independent and dependent variables is not linear.

Accepted Answer

A scatterplot allows for visual inspection of the data points and can reveal non-linear patterns or relationships between the variables.

Question 14

Selling Price and Age of Home Narrative
A real estate agent is interested in knowing whether there is a relationship between the age of a house and the selling price. Listed below are the ages (in years) and selling prices (in $1000s) of a sample of six houses the agent has sold in the past year: 
-Consider the following set of bivariate data:  
a. Plot the data on a scatterplot.
b. Based on the plot in (a), are there any data points that seem unusual (i.e., are there any outliers)? If so, which one or ones?
c. Ignoring any observations you have considered to be unusual, what can be said about the relationship between the variables x and y?

Accepted Answer

The answer of Selling Price and Age of Home Narrative
A...

Question 15

If the correlation coefficient between the independent variable x and the dependent variable y is 0.87, then the best-fitting line would have a slope equal to 0.87.

Accepted Answer

The correlation coefficient measures the strength of the linear relationship between x and y, but it does not determine the slope of the best-fitting line. The slope of the best-fitting line is determined by performing linear regression analysis which involves calculating the equation of the line that minimizes the sum of the squared errors between the predicted and actual values of y based on x.

Question 16

Students' GPA Narrative
A law school administrator was interested in whether a student's score on the entrance exam can be used to predict a student's grade point average (GPA) after one year of law school. The administrator took a random sample of 15 students and computed the following summary information, where x = entrance exam score and y = GPA after one year:      and  .
-Refer to Students' GPA Narrative. Find the correlation between the entrance exam score and the grade point average after one year of law school.

Accepted Answer

The answer of Students' GPA Narrative
A law school administrator was...

Question 17

Gender Differences Narrative
Male and female respondents to a questionnaire about gender differences are categorized into three groups according to their answers, as shown below: 
-Refer to Gender Differences Narrative. Create two pie charts (one for men and one for women) to describe these data.

Accepted Answer

The answer of Gender Differences Narrative
Male and female respondents to...

Question 18

Gender Differences Narrative
Male and female respondents to a questionnaire about gender differences are categorized into three groups according to their answers, as shown below: 
-Refer to Selling Price and Age of Home Narrative. Plot the data on a scatterplot.

Accepted Answer

The answer of Gender Differences Narrative
Male and female respondents to...

Question 19

If two variables have a correlation coefficient equal to 0.005, this means that there is a strong relationship between the two variables.

Accepted Answer

A correlation coefficient of 0.005 indicates a very weak or no relationship between two variables. Correlation coefficients range from -1 to 1, with 0 indicating no correlation and values closer to -1 or 1 indicating stronger relationships.

Question 20

Gender Differences Narrative
Male and female respondents to a questionnaire about gender differences are categorized into three groups according to their answers, as shown below: 
-Refer to Gender Differences Narrative. Create a stacked bar chart to describe these data.

Accepted Answer

The answer of Gender Differences Narrative
Male and female respondents to...

Quiz 3: Describing Bivariate Data

If the linear relationship between the dependent and independent variables is positive, the scatterplot will show the data points on the (x, y) plane moving generally from the lower left corner to the upper right corner.

Gender Differences Narrative Male and female respondents to a questionnaire about gender differences are categorized into three groups according to their answers, as shown below: -Refer to Gender Differences Narrative. Create a side-by-side bar chart to describe these data.

When constructing a scatterplot, the independent variable x is placed on the horizontal axis, and the dependent variable y is placed on the vertical axis.

A perfect correlation between two variables will always produce a correlation coefficient of +1.0.

The scatterplot is a graph that is used to represent the relationship between two quantitative variables.

The best-fitting line relating the dependent variable y to the independent variable x, often called the regression or least-squares line, is found by minimizing the sum of the squared differences between the data points and the line itself.

A scatterplot is particularly useful in determining if the relationship between the independent and dependent variables is not linear.

If the correlation coefficient between the independent variable x and the dependent variable y is 0.87, then the best-fitting line would have a slope equal to 0.87.

Gender Differences Narrative Male and female respondents to a questionnaire about gender differences are categorized into three groups according to their answers, as shown below: -Refer to Gender Differences Narrative. Create two pie charts (one for men and one for women) to describe these data.

Gender Differences Narrative Male and female respondents to a questionnaire about gender differences are categorized into three groups according to their answers, as shown below: -Refer to Selling Price and Age of Home Narrative. Plot the data on a scatterplot.

If two variables have a correlation coefficient equal to 0.005, this means that there is a strong relationship between the two variables.

Gender Differences Narrative Male and female respondents to a questionnaire about gender differences are categorized into three groups according to their answers, as shown below: -Refer to Gender Differences Narrative. Create a stacked bar chart to describe these data.