6 which of the following expressions represents the

6. Which of the following expressions represents the margin of error of a 99% confidence interval for
the slope of the population regression line?
(a)
0.3701
2.576
28
 

 
(b)
( )
2.576 0.3701
(c)
0.3701
2.763
28
 

 
(d) 2.763 0.3701
(e)
( )
2.763 0.3701


Dependent variable is Oxygen Consumption
R-squared = 72.9%
s = 2.81737 with 30 – 2 = 28 degrees of freedom
Variable Coefficient s.e. of Coefficient P-value
Constant 81.589 3.961 ≤0.0001
Run Time -3.2088 0.3701 ≤0.0001

Use the following for questions 7 – 9:
A least squares regression analysis of the cost of tuition at a typical four-year private college versus year
(from 1976 through 2008) produced the following residual plot.
7. Based on this residual plot, which of the following statements must be true?
I. Tuition cost decreased from 1976 through 1982.
II. This regression equation would underestimate tuition cost in 1992.
III The relationship between tuition cost and year is non-linear.
8. The scatterplot of Log (Tuition cost) versus Year shows a strong, positive, linear pattern. Which one
of the following conclusions can be drawn from this information?

9. Below is the computer regression analysis of the relationship between Log (tuition cost) and year.
Which of the following is the correct regression equation from this analysis?
Predictor Coef SE Coef
Constant -51.055 2.997 -17.03 0.000
Year 0.027699 0.001505 18.40 0.000
S = 0.0507261 R-Sq = 97.1% R-Sq(adj) = 96.8%
+
+
+
+
−
T P
10. The typical lifespan for various mammal species in captivity ( L) in years has been related to average
adult size (M) in kilograms according to the regression equation

( )
ln 2.468 0.2 ln L M = +
A typical adult Meerkat weighs about 0.9 kilograms. What is the predicted lifespan of a Meerkat in
captivity, according to this equation?
(a) 2.4 years
(b) 2.6 years
(c) 11.6 years
(d) 14.1 years
(e) 28.8 years

Part 2: Free Response
Show all your work. Indicate clearly the methods you use, because you will be graded on the
correctness of your methods as well as on the accuracy and completeness of your results and
explanations.
11. A psychologist counsels people who are getting divorced. He suspects that it is possible to
predict—among the couples he works with—how long a marriage will last from how long the
divorcing couple’s courtship was before they got married. He selects a random sample of 10 of the
hundreds of couples for whom he has records and performs a regression analysis. Below is
numerical and graphical output from his computer software.