You are given the following information for the data displayed in the scatterplot in Exercise 7.

Least squares prediction equation: Y' = .70(X) +11.80

SS_y = 826.23
SS_y|x = 68.04

Using this information, calculate these measures.

a. The SS measure of the actual gain in accuracy due to the least squares predictions
b. The gain in accuracy relative to the original error variability for the repetitive prediction of the arm circumference mean

c. r²
d. r

Data from exercise 7

In Exercise 5, arm circumference of a sample of females was predicted from waist measurement. In the scatterplot shown below, arm circumference of the same females is predicted from their body mass index (BMI).

Compare the Exercise 5 and Exercise 7 scatterplots. Which appears to be a better predictor of arm circumference, waist measurement or BMI? Why?

Transcribed Image Text:

50 45 40 35 30 25 20 15 20 25 30 35 40 45 50 BMI Arm Circumference (cm)