Section 7 – Correlation and Regression
There will be two points possible per problem
Ten pairs of data yield r = 0.003 and the regression equation y = 2 + 3x. Also, y-bar = 5.0.
What is the best predicted value of y for x = 2?
Refer to Slide 21,22 and 31 in Section 7 slides)
A collection of paired data consists of the number of years that students have studied Spanish and their scores on a Spanish
language proficiency test. A computer program was used to obtain the least squares linear regression line with the
scores on the test as the dependent variable.
The regression equation is: score-hat = 31.55 + 10.90*years
R-squared = 83.0%
What percentage of the total variation in test scores is UNEXPLAINED by the linear relationship between years of study
and test scores? (hint: the unexplained variance would be 1 minus the explained variance, and the explained variance
is represented by R-squared)