Brawn versus brain How is the weight of an animal's brain related to the weight of its body?

Researchers collected data on the brain weight (in grams) and body weight (in kilograms) for 96species of mammals. The figure below is a scatterplot of the logarithm of brain weight against the logarithm of body weight for all 96species. The least-squares regression line for the transformed data is

logy^=1.01+0.72logx

Based on footprints and some other sketchy evidence, some people think that a large apelike animal, called Sasquatch or Bigfoot, lives in the Pacific Northwest. His weight is estimated to be about 280pounds, or 127kilograms. How big is Bigfoot’s brain? Show your method clearly

Short Answer

Expert verified

The brain weight of an animal in relation to its body weight is y^=334.765.

Step by step solution

01

Given Information

It is given in the question:

logy^=1.01+0.72logx

02

Explanation

Bigfoot's weight is estimated to be 280pounds or 127 kilograms. Thus, evaluating the regression line it gives,

logy^=1.01+0.72logx

logy^=1.01+0.72log(127)

logy^=2.52474

y^=102.52474

=334.765

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Most popular questions from this chapter

Park rangers are interested in estimating the weight

of the bears that inhabit their state. The rangers have data

on weight (in pounds) and neck girth (distance around

the neck in inches) for 10 randomly selected bears. Some

regression output for these data is shown below.

A bear was recently captured whose neck girth was 35inchesand whose weight was 466.35pounds. If this bear were added to the data set given above, what would be the effect on the value ofr2?

(a) It would decrease the value of r2because the added

point is an outlier.

(b) It would increase the value of r2because any point

added to the data would increase the percent of variation

in bear weight that can be explained by the least-squares

regression line.

(c) It would increase the value of r2because the added

point lies on the least-squares regression line and is far from

the point (x,y)

(d) It would have no effect on the value ofr2 because the

added point lies far from the point (x,y)

(e) It would have no effect on the value of r2because it lies

on the least-squares regression line.

A distribution that represents the number of cars parked in a randomly selected residential driveway on any night is given by

xi:0 123 4
pi :0.10.20.350.250.15

Which of the following statements is correct?

(a) This is a legitimate probability distribution because each of the pi-values is between 0and 1.

(b) This is a legitimate probability distribution because xiis exactly 10.

(c) This is a legitimate probability distribution because each of the pi-values is between 0and 1and the xiis exactly 10.

(d) This is not a legitimate probability distribution because xiis not exactly 10.

(e) This is not a legitimate probability distribution because role="math" localid="1650523963322" pi is not exactly 1.

In Chapter 3, we examined data on the body weights and backpack weights of a group of eight randomly selected ninth-grade students at the Webb Schools. Some Minitab output from least-squares regression analysis for these data is shown.

2. With such a small sample size, it is difficult to check several of the conditions for regression inference. Assume that the conditions are met. Construct and interpret a 95%confidence interval for the slope of the population regression line.

A 95% confidence interval for the slope B of the population regression line is

A local investment club that meets monthly has 200members ranging in age from 27to81. A cumulative relative frequency graph is shown below. Approximately how many members of the club are more than60 years of age?

(a) 20 (b) 44 (c) 78 (d) 90 (e) 110

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