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Squirrels and their food supply (3.2) Animal species produce more offspring when their supply of food goes up. Some animals appear able to anticipate unusual food abundance. Red squirrels eat seeds from pinecones, a food source that sometimes has very large crops. Researchers collected data on an index of the abundance of pinecones and the average number of offspring per female over 16years.4Computer output from a least-squares 4regression on these data and a residual plot are shown here

a. Is a linear model appropriate for these data? Explain.

b. Give the equation for the least-squares regression line. Define any variables you use.

c. Interpret the values of r2and sin context.

Short Answer

Expert verified

(a) Yes, the linear model is absolutely appropriate for the data.

(b) The equation for the least square regression line is y^=1.4146+0.4399x.

(c) Ther2means variations in variables andsmeans average error.

Step by step solution

01

Part (a) Step 1: Given information

We need to find whether the linear model is appropriate for the given data i.e.

02

Part (a) Step 2: Explanation

We know that

The residual plot shows no discernible trend, and the residuals appear to be centered around0, indicating that the linear model is a good fit for the data.

03

Part (b) Step 1: Given information 

We need to find out the equation for the least-squares regression line.


04

Part (b) Step 2: Explanation

We know that

The general least square eq. is given as

y^=a+bx

And here, a=1.4146,b=0.4399

Therefore, the equation is

role="math" localid="1654085044915" y^=1.4146+0.4399x

Where xis cone index and y^is the average no. of offsprings per female.

05

Part (c) Step 1: Given information

We need to interpret the values of r2and s.


06

Part (c) Step 2: Explanation

We know that

The value of r2=57.2percent indicates that the linear model can explain 57.2percent of the variation between the variables.

The value of s=0.600309indicates that the average prediction error is around 0.600309.

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