College Of The Canyons Math 140 Exam 1 Amy Morrow (Page 5 of 8) in pdf

College Of The Canyons Math 140 Exam 1 Amy Morrow Page 5

College of the Canyons

Math 140 Exam 1

Amy Morrow

(a) Draw the regression line on the graph.

Solution:

(b) What is the explanatory variable?

(b)

Solution: Miles

Solution: tread = 36

.6(40) = 12mm

(d) Explain (in context) what the slope of the line means.

Solution: For every extra thousand miles a taxi is driven, the tire tread depth decreases by

0.6 mm.

(e) Explain (in context) what the y-intercept of the line means.

Solution: For a taxi that has not been driven any miles, the starting tread depth is 36mm.

(f) Explain (in context) what R means.

Solution: 74% of the variation in tread depth is explained by the linear relationship with miles

driven.

(g) The correlation r =

(g)

Solution:

r =

0.74 = 0.86. Since the slope is negative, we have r =

0.86.

(h) In this context, what does a negative residual mean?

Solution: A taxi has a smaller tread depth for the miles driven than was predicted by the

model.

(i) Based on our regression, can we conclude that driving more miles will lead to a decrease in tire

tread depth? Explain

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College Of The Canyons Math 140 Exam 1 Amy Morrow Page 5