
Concept explainers
a)
To test an appropriate hypothesis.
a)

Answer to Problem 30E
There is sufficient evidence that the slope is non zero and there is a significant association between sales and profits.
Explanation of Solution
Given:
Formula:
Test statistic:
The null and alternative hypotheses:
Test statistic:
The degrees of freedom = df = 77
Therefore, p-value would be,
P-value = 0 …Using excel formula, =TDIST(12.333,77,2)
Decision: P-value < 0.05, reject H0.
Conclusion: There is sufficient evidence that the slope is non zero and there is a significant association between sales and profits.
b)
To explain whether the company’s sales serve as a useful predictor of its profits.
b)

Answer to Problem 30E
The company’s serve as useful predictor of its profits.
Explanation of Solution
Given:
The R-square = 66.2% which is moderately high and standard deviation is 466.2 which is much higher than standard error of coefficient. Therefore, the company’s serve as useful predictor of its profits.
Chapter 27 Solutions
Stats: Modeling the World Nasta Edition Grades 9-12
Additional Math Textbook Solutions
Elementary Statistics: Picturing the World (7th Edition)
Thinking Mathematically (6th Edition)
University Calculus: Early Transcendentals (4th Edition)
Introductory Statistics
Elementary Statistics
Calculus: Early Transcendentals (2nd Edition)
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