Week 7 Assignment
1. What does regression tell us? How is an r value used in regression?
2. What is interpolation? What is extrapolation? Why is it dangerous to extrapolate outside the experimental region (the range of your data)?
3. Given the following
Book
Pages (x variable)
Price (y variable)
A
250
$5.20
B
317
$5.95
C
234
$4.95
D
417
$7.25
E
301
$5.95
F
315
$6.00
G
389
$6.95
a. Create a scatter diagram which shows the trendline (this is the regression line) and provides the coefficient of determination on the graph itself.
b. What is the equation of the trendline from the graph? (Just copy it from your graph)
c. According to the equation of the trendline from your graph, if a book had 357 pages, how much should it cost?
d. According to the equation of the trendline from your graph, if a book costs $8.50, how many pages should it have?
e. In part d, were you interpolating or extrapolating? How do you know? How confident are you that the number of pages would really be what you calculated it to be? Why?
4. You are presented with several values for Pearson’s product moment correlation coefficient ( r ). Which one shows the strongest relationship? Why?
a. -0.97
b. -0.60
c. 0.15
d. 0.89
e. 0.95
f. 0
