Bivariable
25
The formula for a regression equation is Y' = 3X - 2. What would be the predicted Y score for a person scoring 4 on X?

Plug X = 4 into the equation to find Y'= 3(4) - 2 = 10
10
0.0
Suppose it is possible to predict a person's score on Test B from the person's score on Test A. The regression equation is:
B' = 2.3A + 9.5. What is a person's predicted score on Test B assuming this person got a 40 on Test A?

Plug A = 40 into the equation to find B'= 2.3(40) + 9.5 = 101.5
101.5
0.0
Suppose a person got a score of 32.5 on Test A and a score of 95.25 on Test B.
Using the same regression equation as in the previous problem (B' = 2.3A + 9.5), what is the error of prediction for this person?

Predicted value, B' = 2.3(32.5) + 9.5 = 84.25; Error of prediction = B - B' = 95.25 - 84.25 = 11
11
0.0
What is the most common criterion used to determine the best-fitting line?

false
The line that goes through the most points
false
The line that has the same number of points above it as below it
true
The line that minimizes the sum of squared errors of prediction
The most common criterion used to determine the best-fitting line is the line that minimizes the sum of squared errors of prediction. This line does not need to go through any of the actual data points, and it can have a different number of points above it and below it.
The mean of X is 3 and the mean of Y is 7. The regression line that predicts Y from X necessarily goes through the point (3,7).

true
True
false
False
Someone who scored the mean on X would be predicted to score the mean on Y.
You want to be able to predict a woman's shoe size from her height. You have gathered this information from your female classmates. The mean height of women in your class is 64 inches, and the standard deviation is 2 inches.
The mean shoe size is 8, and the standard deviation is 1. The correlation between these two variables is .5. What is the slope of the regression line?

b = r(sY/sX) = .5(1/2) = .25
.25
0.0
What is the slope of the regression line when predicting Y from X?

0
0.01
b = showCorrectAnswer