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Chapter 3: Q. 1.1 (page 169)

Some data were collected on the weight of a male white laboratory rat for the first 25 weeks after its birth. A scatterplot of the weight (in grams) and time since birth (in weeks) shows a fairly strong, positive linear relationship. The linear regression equation weight = 100 + 40(time) models the data fairly well.

1. What is the slope of the regression line? Explain what it means in context.

Short Answer

Expert verified

The slope of the regression line(b)is40.

Step by step solution

01

Given

We are given the linear regression equation of time on weight:

weight=100+40(time)

02

Calculations

We know that for the given linear regression equation of the form:

y=a+bx, the slope is b.

Therefore,

For the given equation we have, b=40.

Therefore the slope of linear regression equation is40.

03

Explanation

The value of slope b=40means that we for a unit increase in time the weight increases by 40 units, provided a remains constant.

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Most popular questions from this chapter

Southern education For a long time, the South has lagged behind the rest of the United States in the performance of its schools. Efforts to improve education have reduced the gap. We wonder if the South stands out in our study of state average SAT Math scores.

The figure below enhances the scatterplot in Figure 3.2(page 144) by plotting 12southern states in red.

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Interpret the value of this subject’s residual in context.

For the least-squares regression of fat gain on NEA,r2=0.606. Which of the following gives a correct interpretation of this value in context?

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(d) 77.8%of the variation in fat gain is accounted for by the least-squares line.
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