Common Core: High School - Statistics and Probability : Interpreting Categorical & Quantitative Data

Study concepts, example questions & explanations for Common Core: High School - Statistics and Probability

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All Common Core: High School - Statistics and Probability Resources

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Example Questions

Example Question #6 : Compute And Interpret The Correlation Coefficient Of A Linear Fit: Ccss.Math.Content.Hss Id.C.8

Which of the following graphs possesses a correlation coefficient indicative of a random distribution?

 

Possible Answers:

Plot8.3

Plot8.5

Plot8.2

Plot8.4

Plot8.1

Correct answer:

Plot8.5

Explanation:

In order to solve this problem, we need to understand several key concepts associated with correlations. First, let's discuss what is meant by the term "correlation." A correlation exists when two variables possess a statistical relationship with one another. It is important to note that correlation in no way relates to causation. Causation implies that one variable causes change in the other, while correlation simply denotes the observation of a trend between two variables.

Second, let's observe the differences between slope and the correlation coefficient. The correlation coefficient is denoted by the following variable.

It is mathematically defined as a goodness of fit measure that is calculated by dividing the covariance of the samples by the product of the sample's standard deviations. This is also known as Pearson's r and it describes the strength and direction of a linear relationship between two variables. On the other hand, the slope is described as the gradient of a line and is key component of the slope intercept formula:

This formula provides information about two key parts of a line: the slope and y-intercept.

The slope is commonly defined as rise over run. In other words it is the change in y-values across points divided by the change in x-values. It is calculated using the following formula:

In this formula, the x and y-values come from two points from the line written in the following format: 

It is important to note that slopes can be positive or negative. A positive slope moves upward from left to right while a negative slope moves downward. Even though the correlation coefficient will share the same sign as the slope, they mean entirely different things.

We have discussed the following distinctions: the differences between what is meant correlation and causation as well as the differences between the correlation coefficient and the slope. Now, we can start to solve the problem. 

First, lets learn how calculate the correlation coefficient from coefficient of determination. The coefficient of determination is denoted by the following:

We can calculate the correlation coefficient by taking the square root of the coefficient of determination:

After we calculate the correlation coefficient, we need to know how to evaluate what the number means. We can pick the sign based on the position of the trendline or slope. If the slope is negative then the trendline travels downward from the left to the right of the graph. On the other hand, if the slope is positive then the trendline travels upwards from the left to the right side of the graph. Below is a table of values that explains the relationships between points based upon the correlation coefficient. A correlation coefficient close to zero indicates a random distribution.

Screen shot 2016 01 18 at 1.41.50 pm

We will start solving this problem by picking out the graph with obvious positive or negative trends and excluding them.

Plot8.1

Plot8.2

Plot8.3

The last, two graph's have a near horizontal trendline, which is indicative of a random distribution:

Plot8.4

Plot8.5

This graph possesses a trendline with the following coefficient of determination:

We must take the square root of this measure calculated using statistical technology (this standard does not require you to calculate the correlation coefficient, only to interpret it).

This trendline's correlation coefficient is most indicative of a random distribution.

 

 

Example Question #181 : High School: Statistics & Probability

Which of the following graphs possesses a correlation coefficient indicative of a random distribution?

Possible Answers:

Plot10.2

Plot10.1

Plot10.3

Plot10.4

Plot10.5

Correct answer:

Plot10.5

Explanation:

In order to solve this problem, we need to understand several key concepts associated with correlations. First, let's discuss what is meant by the term "correlation." A correlation exists when two variables possess a statistical relationship with one another. It is important to note that correlation in no way relates to causation. Causation implies that one variable causes change in the other, while correlation simply denotes the observation of a trend between two variables.

Second, let's observe the differences between slope and the correlation coefficient. The correlation coefficient is denoted by the following variable.

It is mathematically defined as a goodness of fit measure that is calculated by dividing the covariance of the samples by the product of the sample's standard deviations. This is also known as Pearson's r and it describes the strength and direction of a linear relationship between two variables. On the other hand, the slope is described as the gradient of a line and is key component of the slope intercept formula:

This formula provides information about two key parts of a line: the slope and y-intercept.

The slope is commonly defined as rise over run. In other words it is the change in y-values across points divided by the change in x-values. It is calculated using the following formula:

In this formula, the x and y-values come from two points from the line written in the following format: 

It is important to note that slopes can be positive or negative. A positive slope moves upward from left to right while a negative slope moves downward. Even though the correlation coefficient will share the same sign as the slope, they mean entirely different things.

We have discussed the following distinctions: the differences between what is meant correlation and causation as well as the differences between the correlation coefficient and the slope. Now, we can start to solve the problem. 

First, lets learn how calculate the correlation coefficient from coefficient of determination. The coefficient of determination is denoted by the following:

We can calculate the correlation coefficient by taking the square root of the coefficient of determination:

After we calculate the correlation coefficient, we need to know how to evaluate what the number means. We can pick the sign based on the position of the trendline or slope. If the slope is negative then the trendline travels downward from the left to the right of the graph. On the other hand, if the slope is positive then the trendline travels upwards from the left to the right side of the graph. Below is a table of values that explains the relationships between points based upon the correlation coefficient. A correlation coefficient close to zero indicates a random distribution.

Screen shot 2016 01 18 at 1.41.50 pm

We will start solving this problem by picking out the graph with obvious positive or negative trends and excluding them.

Plot10.1

Plot10.2

Plot10.3

The last, two graph's have a near horizontal trendline, which is indicative of a random distribution:

Plot10.4

Plot10.5

This graph possesses a trendline with the following coefficient of determination:

We must take the square root of this measure calculated using statistical technology (this standard does not require you to calculate the correlation coefficient, only to interpret it).

This trendline's correlation coefficient is most indicative of a random distribution.

 

 

Example Question #182 : Interpreting Categorical & Quantitative Data

Which of the following graphs possesses a correlation coefficient indicative of a random distribution?

Possible Answers:

Plot11.1

Plot11.2

Plot11.4

Plot11.3

Plot11.5

Correct answer:

Plot11.5

Explanation:

In order to solve this problem, we need to understand several key concepts associated with correlations. First, let's discuss what is meant by the term "correlation." A correlation exists when two variables possess a statistical relationship with one another. It is important to note that correlation in no way relates to causation. Causation implies that one variable causes change in the other, while correlation simply denotes the observation of a trend between two variables.

Second, let's observe the differences between slope and the correlation coefficient. The correlation coefficient is denoted by the following variable.

It is mathematically defined as a goodness of fit measure that is calculated by dividing the covariance of the samples by the product of the sample's standard deviations. This is also known as Pearson's r and it describes the strength and direction of a linear relationship between two variables. On the other hand, the slope is described as the gradient of a line and is key component of the slope intercept formula:

This formula provides information about two key parts of a line: the slope and y-intercept.

The slope is commonly defined as rise over run. In other words it is the change in y-values across points divided by the change in x-values. It is calculated using the following formula:

In this formula, the x and y-values come from two points from the line written in the following format: 

It is important to note that slopes can be positive or negative. A positive slope moves upward from left to right while a negative slope moves downward. Even though the correlation coefficient will share the same sign as the slope, they mean entirely different things.

We have discussed the following distinctions: the differences between what is meant correlation and causation as well as the differences between the correlation coefficient and the slope. Now, we can start to solve the problem. 

First, lets learn how calculate the correlation coefficient from coefficient of determination. The coefficient of determination is denoted by the following:

We can calculate the correlation coefficient by taking the square root of the coefficient of determination:

After we calculate the correlation coefficient, we need to know how to evaluate what the number means. We can pick the sign based on the position of the trendline or slope. If the slope is negative then the trendline travels downward from the left to the right of the graph. On the other hand, if the slope is positive then the trendline travels upwards from the left to the right side of the graph. Below is a table of values that explains the relationships between points based upon the correlation coefficient. A correlation coefficient close to zero indicates a random distribution.

Screen shot 2016 01 18 at 1.41.50 pm

We will start solving this problem by picking out the graph with obvious positive or negative trends and excluding them.

Plot11.1

Plot11.2

Plot11.3

The last, two graph's have a near horizontal trendline, which is indicative of a random distribution:

Plot11.4

Plot11.5

This graph possesses a trendline with the following coefficient of determination:

We must take the square root of this measure calculated using statistical technology (this standard does not require you to calculate the correlation coefficient, only to interpret it).

This trendline's correlation coefficient is most indicative of a random distribution.

 

 

Example Question #183 : Interpreting Categorical & Quantitative Data

Which of the following graphs possesses a correlation coefficient indicative of a random distribution?

Possible Answers:

Plot12.2

Plot12.5

Plot12.4

Plot12.1

Plot12.3

Correct answer:

Plot12.5

Explanation:

In order to solve this problem, we need to understand several key concepts associated with correlations. First, let's discuss what is meant by the term "correlation." A correlation exists when two variables possess a statistical relationship with one another. It is important to note that correlation in no way relates to causation. Causation implies that one variable causes change in the other, while correlation simply denotes the observation of a trend between two variables.

Second, let's observe the differences between slope and the correlation coefficient. The correlation coefficient is denoted by the following variable.

It is mathematically defined as a goodness of fit measure that is calculated by dividing the covariance of the samples by the product of the sample's standard deviations. This is also known as Pearson's r and it describes the strength and direction of a linear relationship between two variables. On the other hand, the slope is described as the gradient of a line and is key component of the slope intercept formula:

This formula provides information about two key parts of a line: the slope and y-intercept.

The slope is commonly defined as rise over run. In other words it is the change in y-values across points divided by the change in x-values. It is calculated using the following formula:

In this formula, the x and y-values come from two points from the line written in the following format: 

It is important to note that slopes can be positive or negative. A positive slope moves upward from left to right while a negative slope moves downward. Even though the correlation coefficient will share the same sign as the slope, they mean entirely different things.

We have discussed the following distinctions: the differences between what is meant correlation and causation as well as the differences between the correlation coefficient and the slope. Now, we can start to solve the problem. 

First, lets learn how calculate the correlation coefficient from coefficient of determination. The coefficient of determination is denoted by the following:

We can calculate the correlation coefficient by taking the square root of the coefficient of determination:

After we calculate the correlation coefficient, we need to know how to evaluate what the number means. We can pick the sign based on the position of the trendline or slope. If the slope is negative then the trendline travels downward from the left to the right of the graph. On the other hand, if the slope is positive then the trendline travels upwards from the left to the right side of the graph. Below is a table of values that explains the relationships between points based upon the correlation coefficient. A correlation coefficient close to zero indicates a random distribution.

Screen shot 2016 01 18 at 1.41.50 pm

We will start solving this problem by picking out the graph with obvious positive or negative trends and excluding them.

Plot12.1

Plot12.2

Plot12.3

The last, two graph's have a near horizontal trendline, which is indicative of a random distribution:

Plot12.4

Plot12.5

This graph possesses a trendline with the following coefficient of determination:

We must take the square root of this measure calculated using statistical technology (this standard does not require you to calculate the correlation coefficient, only to interpret it).

This trendline's correlation coefficient is most indicative of a random distribution.

 

 

Example Question #1 : Correlation Vs. Causation: Ccss.Math.Content.Hss Id.C.9

Violent crime has a strong positive correlation with ice cream sales. What can be inferred from this?

Possible Answers:

The increase in ice cream sales causes the increase in violent crime.

While the two events are correlated, more evidence is needed to determine whether or not this correlation is coincidental.

The correlation between ice cream sales and violent crime is the result of some error in the statistical study.

The two events are causally related.

The increase in violent crime causes the increase in ice cream sales.

Correct answer:

While the two events are correlated, more evidence is needed to determine whether or not this correlation is coincidental.

Explanation:

 

 

 

Example Question #1 : Correlation Vs. Causation: Ccss.Math.Content.Hss Id.C.9

Which choice best describes the relationship between the variables in the following scatterplot?

Ice cream vs sharks

Possible Answers:

Ice cream consumption causes shark attacks

Shark attacks induce ice cream consumption

None of these

The variables possess a correlation due to a lurking or linking variable

Correct answer:

The variables possess a correlation due to a lurking or linking variable

Explanation:

In order to properly solve this question, we need to understand the differences between what is meant by correlation and causation. A correlation refers to the strength of the linear association between two quantitative variables. On the other hand, causation indicates that the change in one variable is the cause of change in another.

Correlation can be used as an indicator of causal relationships; however, experimentation is needed to properly identify which variable is actually causing the observed change. Scientific experimentation identifies causality through he implementation of laboratory procedures in a controlled setting. When variables are controlled, causation can be determined through observation and repeated tests.

Several logical fallacies explain why correlation does not directly imply causation. First, cause-and-effect is not determined by two events occurring simultaneously. In other words, events that occur together do not necessarily cause one another. Second, causality is not determined by an event preceding another temporally. In other words, this means that event B is not always a consequence of event A simply because event A occurs before event B.

Lurking or linking variables can cause events that are highly correlated to one another appear to have a casual relationship. This is because a third separate factor may be inducing change in the two variables. 

Now, let's solve this problem. It asks us to describe the relationship in the scatterplot. We know that there is a positive relationship between the two variables; however, if we think critically we know that shark attacks and ice cream sales are independent of one another. The answers that suggest causality are incorrect. A linking or lurking variable—in this case warm temperatures—is causing change in both of the variables. In other words, warmer temperatures cause individuals to purchase ice cream and frequent the beach. Greater populations of beach goers increase the probability of shark attacks.

Example Question #1 : Correlation Vs. Causation: Ccss.Math.Content.Hss Id.C.9

Which choice best describes the relationship between the variables in the following scatterplot?


Attendance vs sharks

Possible Answers:

Beach attendance causes shark attacks

Beach attendance is negatively correlated with shark attacks

Beach attendance is positively correlated with shark attacks

Shark attacks cause beach attendance

Correct answer:

Beach attendance is positively correlated with shark attacks

Explanation:

In order to properly solve this question, we need to understand the differences between what is meant by correlation and causation. A correlation refers to the strength of the linear association between two quantitative variables. On the other hand, causation indicates that the change in one variable is the cause of change in another.

Correlation can be used as an indicator of causal relationships; however, experimentation is needed to properly identify which variable is actually causing the observed change. Scientific experimentation identifies causality through he implementation of laboratory procedures in a controlled setting. When variables are controlled, causation can be determined through observation and repeated tests.

Several logical fallacies explain why correlation does not directly imply causation. First, cause-and-effect is not determined by two events occurring simultaneously. In other words, events that occur together do not necessarily cause one another. Second, causality is not determined by an event preceding another temporally. In other words, this means that event B is not always a consequence of event A simply because event A occurs before event B.

Lurking or linking variables can cause events that are highly correlated to one another appear to have a casual relationship. This is because a third separate factor may be inducing change in the two variables. 

Now, let's solve this problem. It asks us to describe the relationship in the scatterplot. We know that there is a positive relationship between the two variables; however, if we think critically we know that beach attendance and shark attacks do not cause one another. The answers that suggest causality are incorrect. There are many factors that influence shark attacks on beaches—beach attendance is one of them. For example, if no one goes to the beach, then a shark located at the beach can attack no one. Increased beach attendance is positively correlated with shark attacks but further investigation is needed to determine if this causes the attacks. A mating cycle, global warming, or changes in food sources could all induce a shark attack. Beach attendance is only one factor correlated with this phenomenon.

All Common Core: High School - Statistics and Probability Resources

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