Linear Regression

Question 1

What does a slope of 2 mean?

Answer 1

That every 1-unit change in X yields a 2-unit change in Y

Question 2

What is the formula to find the slope?

Answer 2

Rise/Run

Question 3

What is the formula to find linear?

Answer 3

Y = Mx + B

Question 4

What measures the relative strength of the linear relationship between two variables?

Answer 4

Correlation

Question 5

True or False:

Correlation is unit-less

Answer 5

True

Question 6

What is the range of correlation?

Answer 6

-1 and 1

Question 7

Fill in the Blanks:

The closer correlation is to -1, the ______ the ______ linear relationship

Answer 7

1. Stronger

1. Negative

Question 8

Fill in the Blanks:

The closer correlation is to 1, the ______ the ______ linear relationship

Answer 8

1. Stronger

2. Positive

Question 9

Fill in the Blanks:

The closer correlation is to 0, the ______ any ______ linear relationship

Answer 9

1. Weaker

2. Positive

Question 10

What measures the strength and direction of the linear relationship?

Answer 10

The Coefficient of Correlation

Question 11

How do you know when a scatter plot has a correlation coefficient of -1?

Answer 11

The dots form a downward line

Question 12

How do you know when a scatter plot has a correlation coefficient of 1?

Answer 12

The dots form a upward line

Question 13

How do you know when a scatter plot has a correlation coefficient of 0?

Answer 13

The dots form a straight line

Question 14

How do you know when a linear correlation has no relationship on a scatter plot?

Answer 14

The dots are scattered everywhere

Question 15

How do you know when a linear correlation has a relationship on a scatter plot?

Answer 15

The dots are clustered together

Question 16

True or False:

In linear correlation, the two variables are treated as equals

Answer 16

True

Question 17

Fill in the Blanks:

In linear regression, one variable is considered the ________ variable while the other is considered the ________ variable

Answer 17

1. Independent

2. Dependent

Question 18

In linear regression which variable is considered the independent variable?

Answer 18

X

Question 19

In linear regression which variable is considered the dependent variable?

Answer 19

Y

Question 20

What is another name for the x variable in linear regression?

Answer 20

The predictor

Question 21

What is another name for the y variable in linear regression?

Answer 21

The outcome

Question 22

What is the difference between linear regression and correlation?

Answer 22

Correlation tells if two things travel together while Regression tells if one thing can predict another

Question 23

List the 4 things that linear regression assumes

Answer 23

1. The relationship between X and Y is linear
2. Y is distributed normally at each value of X
3. The variance of Y at every value of X is the same
4. The observations are independent

Question 24

Which function provides the correlation coefficient (r)?

Answer 24

The CORREL function

Question 25

Which function provides r-squared?

Answer 25

The RSQ function

Question 26

Which function provides the y-intercept?

Answer 26

The INTERCEPT function

Question 27

Which function returns the best fit line against x values?

Answer 27

The TREND function

Question 28

What should you do if you have more than 1 causal (i.e. X) variable?

Answer 28

Use multiple linear regressions

Question 29

What is the percentage variation explained by the X variables?

Answer 29

The adjusted r square

Question 30

What does it indicate when the significance F is < .05?

Answer 30

That regression is significant at 95% confidence level

Question 31

What does it indicate when the p-values of variables is < .05?

Answer 31

That variables are significant at 95% confidence level

Question 32

What arises when two variables that measure the same thing or similar things are both included in a multiple regression model?

Answer 32

Multicollinearity

Question 33

What is a numeric variable that represents categorical data?

Answer 33

A dummy variable

Question 34

What is the dummy variable also known as?

Answer 34

The indicator variable

Question 35

List the 4 steps to using multiple regression in Excel

Answer 35

1. Input your Y and X variables into the input box 2. Select where you want the output to go 3. Drop X variables that fail the P-value test 4. Rerun your model

Question 36

True or False: Name of the game in multiple regression is to use the maximum number of variables required to predict Y

Answer 36

False, minimum

Question 37

What are 3 examples of categorical data?

Answer 37

Gender, race, and political affiliation

Question 38

What is the regression equation?

Answer 38

Income = b0 + b1X1+ b2X2