Statistics and Regression Analysis Quiz

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Questions and Answers

What does having an association between segments in a bar graph indicate?

The segments are arranged in ascending order.
The segments are identical in size.
The segments have no numerical significance.
The segments represent different categories or variables. (correct)

What is the role of the explanatory variable in a graph?

To predict changes in the response variable. (correct)
To serve as a constant reference point.
To illustrate the relationship between two unrelated variables.
To represent the outcome metric.

If a correlation coefficient $r = -0.75$ is observed, how can this relationship be characterized?

There is no correlation.
There is a weak negative correlation.
There is a strong positive correlation.
There is a moderate negative correlation. (correct)

Why is the statement 'Causation does not equal correlation' significant in data analysis?

It highlights that one event occurring does not necessarily result in another. (A)

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What happens to a linear regression line (LSRL) when an outlier is added?

It may be significantly influenced and possibly skewed. (C)

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What can be inferred if a residual plot shows no clear pattern?

The chosen model is likely a good fit for the data. (D)

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What does a high R-squared value signify in a regression model?

The model accounts for a high percentage of the variance in the data. (D)

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How does removing an outlier affect the least squares regression line (LSRL)?

It will typically lead to a better fit of the regression line. (B)

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When an LSRL is used for extrapolation, what should be considered?

Extrapolation should be avoided outside the x-interval of actual data. (C)

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What characteristic indicates a poor model using residual plots?

A visible pattern among the residuals. (B)

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Flashcards

Explanatory Variable

The explanatory variable is the one that is being manipulated or changed to see its effect on the response variable.

Response Variable

The response variable is the outcome or result that is being measured.

Strong Association

A strong association means that the segments in each bar of a graph are different, indicating a clear relationship between the variables.

Weak Association

A weak association means that the segments in each bar of a graph are similar, indicating a less clear relationship between the variables.

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Correlation Coefficient (r)

A correlation coefficient (r) measures the strength and direction of a linear relationship between two variables.

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Strong Positive Relationship

A correlation coefficient (r) close to 1 indicates a strong positive relationship, meaning that as one variable increases, the other tends to increase as well.

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Strong Negative Relationship

A correlation coefficient (r) close to -1 indicates a strong negative relationship, meaning that as one variable increases, the other tends to decrease.

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Correlation Doesn't Imply Causation

Correlation does not imply causation. Just because two variables are correlated does not mean that one causes the other.

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Extrapolation

Extrapolation is using a regression model to predict values outside the range of the original data. It is not reliable and can lead to inaccurate predictions.

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