Assignment 9
Lesson 9 – Least Squares Regression
Problem 1.
BDV19543: Body Fat
It is difficult to accurately determine a person's body fat percentage without immersing them in water.
Researchers hoping to make a good estimate immersed 20 male subjects, then measured their waists
and recorded their weights. Data is shown in the attached datafile.
A.
Create a model (write an equation) to predict body fat from weight.
B.
What is the independent variable?
C.
Create a scatterplot and add the regression line.
D.
Find the correlation coefficient.
E.
Do you think a linear model is appropriate? Explain.
F.
Find the yintercept of the model and interpret. Does it have a practical meaning?
G.
Find the slope of the model and interpret.
H.
Find the sum of squared residuals.
I.
Using the regression model you found in Part A, predict the body fat percentage for a male who
weights 175 pounds.
J.
What is the residual for a male who weighs 175 pounds and is 6% body fat? (Case 1)
K.
Predict the body fat percentage for a male who weights 200 pounds.
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 Spring '11
 Thaler
 Least Squares, Regression Analysis, body fat percentage

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