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Name_________________________
STA 6167
Exam #1
Spring 2006
Attached are four pages of PROC REG output from regression models relating height (ht) to left
hand span (lspan) and right hand span (rspan) in a group of 41 students.
1. Page 1 of the output shows the results of regressing ht on lspan.
a. (15) Write the fitted regression equation for predicting ht based on lspan and construct a 95%
CI for the slope.
Equation:
95% CI for slope:
b. (10) If Mary had lspan=8 and Jim had lspan=10, how much taller would you predict Jim is
than Mary?
c. (10) Write the interpretation of R
2
=.3566.
d. (10) Page 2 shows the results of regressing ht on rspan.
Do you think it would matter very
much which hand is used to predict height?
Explain your answer.
e. (10) Page 3 shows the results of regressing ht on both lspan and rspan.
There is an obvious
problem with trying to make a meaningful interpretation of the lspan regression coefficient.
What caused this problem?
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View Full Documentf. (10) Compute predicted heights for Mary and Jim using regression equations from pages 1 and
3, assuming lspan=rspan for each person.
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 Fall '08
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