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Chapter 3: Q. 1.2 (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.

2. What’s the y intercept? Explain what it means in context.

Short Answer

Expert verified

The value of y-intercept ais100

Step by step solution

01

Given

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

weight=100+40(time)

02

Calculation

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

y=a+bx

The value of y-intercept is a.

Therefore value of y-intercept for the given equation will be100.

03

Interpretation

The value of y-intercept that is a=100means that if we were to keep the value of time 0, weight will be 100. That is initally we assume the weight to be100units.

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