Introduction to Regression

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Questions 1-3

Question 1.

Which variable is represented by X?

The response variable

The explanatory variable

Any potential lurking variable

A confounded variable

Incorrect. The letter “X” is always used to represent the explanatory (or predictor) variable.

Correct. The letter “X” is always used to represent the explanatory (or predictor) variable.

Incorrect. Try again.

Question 2.

Which variable is represented by Y?

The explanatory variable

Any potential lurking variable

The response variable

Incorrect. The letter “Y” is always used to represent the response (or the predicted) variable.

Correct. The letter “Y” is always used to represent the response (or the predicted) variable.

Incorrect. Try again.

Question 3.

What do we predict with a statistical model?

The value of Y for a given value of X.

The deviations of the X values from the statistical model.

The value of X for a given value of Y.

Incorrect. We use “X” to predict “Y”.

Correct. We use “X” to predict “Y”.

Incorrect. Try again.

Questions 4-5

172

Question 4.

Which symbol represents slope in a statistical model?

Incorrect. In this course we use the lower case letter “b” to represent slope.

Correct. In this course we use the lower case letter “b” to represent slope.

Incorrect. Try again.

Question 5.

What does the symbol ŷ represent?

The predicted y value

An observed y value

The y-intercept value

Incorrect. The symbol ŷ is pronounced “y-hat” and represents the predicted y value.

Correct. The symbol ŷ is pronounced “y-hat” and represents the predicted y value.

Incorrect. Try again.

Questions 6-11

355

Question 6.

What does y-intercept tell us?

The value of Y when X = 0

The change in X for every one unit increase in Y

The change in Y for every one unit increase in X

The value of X when Y = 0

Incorrect. y-intercept is the point at which the line intercepts the y-axis. So, it is the value of Y when X = 0.

Correct. y-intercept is the point at which the line intercepts the y-axis. So, it is the value of Y when X = 0.

Incorrect. Try again.

Question 7.

What does slope tell us?

The value of Y when X = 0

The value of X when Y = 0

The change in X for every one unit increase in Y

The change in Y for every one unit increase in X

Incorrect. Slope is often described as “rise over run.” The rise is in Y and the run is in X. So, slope tells us the change in Y for every one unit increase in X.

Correct. Slope is often described as “rise over run.” The rise is in Y and the run is in X. So, slope tells us the change in Y for every one unit increase in X.

Incorrect. Try again.

Question 8.

As X increases by one unit, what happens to Y when slope is negative?

Y decreases

Y increases

Y stays the same.

Incorrect. When slope is positive, Y increases as X increases.

Correct. When slope is positive, Y increases as X increases.

Incorrect. Try again.

Question 9.

As X increases by one unit, what happens to Y when slope is positive?

Y increases

Y stays the same.

Y decreases

Incorrect. When slope is positive, Y increases as X increases.

Correct. When slope is positive, Y increases as X increases.

Incorrect. Try again.

Question 10.

If you want to predict GPA from hours spent studying per week for students at a private university, what is the response variable?

GPA

Whether student studies

Hours spent studying per week

All students at the private university

Incorrect. We use X to predict Y and Y is the response variable. Since we want to predict GPA, the response variable is GPA.

Correct. We use X to predict Y and Y is the response variable. Since we want to predict GPA, the response variable is GPA.

Incorrect. Try again.

Question 11.

If you want to predict car mileage (in miles per gallon) from car weight, what is the explanatory variable?

Car weight

Car mileage

All cars

Incorrect. We use X to predict Y and X is the explanatory or predictor variable. Since we want to use car weight to predict car mileage, the explanatory variable is car weight.

Correct. We use X to predict Y and X is the explanatory or predictor variable. Since we want to use car weight to predict car mileage, the explanatory variable is car weight.

Incorrect. Try again.

StatTutor Lesson - Introduction to Regression

Questions 1-3

Question 1.

Question 2.

Question 3.

Questions 4-5

Question 4.

Question 5.

Questions 6-11

Question 6.

Question 7.

Question 8.

Question 9.

Question 10.

Question 11.