4. Given the following data set:
|
x
|
1
|
3
|
7
|
9
|
13
|
15
|
|
y
|
1
|
5
|
8
|
10
|
11
|
13
|
Find the correlation coefficient.
Using this to predict the value of y when x = 2.
Find the root mean square error.
5. For 1000 men age 18 - 24 in the HANES sample
Average height (X) = 75 inches SDx = 3 inches
Average weight (Y) = 160 pounds SDy = 20 pounds
Correlation r = .6
One man in the sample was 65 inches tall what is his expected weight?
6. In a certain class, midterm score average out 70 with an SD of 15, as do scores on the final. The correlation between midterm scores and final scores is about 0.40. The scatter diagram is football-shaped.
a. Predict the final score for a student whose midterm score is
(i) 75 (ii) 30 (ii) 60 (iv) unknown
b. Predict the midterm score for a student whose final score is 45.
c. Apparently low-scoring students on the midterm do better on the final, but low -scoring student on the final did better on the midterm. How is this possible?