7

A group of 50 individuals has been surveyed on the number of hours devoted each day to sleeping and watching TV. The responses are summarized in the following table:

No. of sleeping hours (x) 6 7 8 9 10
No. of hours of television (y) 4 3 3 2 1
Absolute frequencies (fi) 3 16 20 10 1

1 Calculate the correlation coefficient.

2 Determine the equation of the regression line of y on x.

3 If a person sleeps eight hours, how many hours of TV are they expected to watch?


xi yi fi xi · fi xi2 · fi yi · fi yi2 · fi xi · yi · fi
6 4 3 18 108 12 48 72
7 3 16 112 784 48 144 336
8 3 20 160 1,280 60 180 480
9 2 10 90 810 20 40 180
10 1 1 10 100 1 1 10
    50 390 3,082 141 413 1,078

Correlation and Regression Calculations

Correlation and Regression Calculations

Correlation and Regression Calculations

Correlation and Regression Calculations

Correlation and Regression Calculations

There is a strong negative correlation.

Correlation and Regression Solution

Correlation and Regression Solution