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9.4 EVALUATING THE REGRESSION EQUATION 429
(a)
Close fit, large r 2
(b)
Poor fit, small r 2
(c)
r 2 = 1
(d)
r 2 0
FIGURE 9.4.5 as a measure of closeness-of-fit of the sample regression line to
the sample observations.
r 2
←
Solution:
The steps in the hypothesis testing procedure are as follows:
1. Data. The data were described in the opening statement of Example
9.3.1.
2. Assumptions. We presume that the simple linear regression model and
its underlying assumptions as given in Section 9.2 are applicable.
3. Hypotheses.
H 0 : b 1 = 0
H A : b 1 Z 0
a = .05