5

The values of two variables x and y are distributed according to the following table:

y/x 100 50 25
14 1 1 0
18 2 3 0
22 0 1 2

It calls for:

1 Calculate the covariance.

2 Obtain and interpret the linear correlation coefficient.

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


Turn the double entry table into a single table.

xi yi fi xi · fi xi2 · fi yi · fi yi2 · fi xi · yi · fi
100 14 1 100 10,000 14 196 1,400
100 18 2 200 20,000 36 648 3,600
50 14 1 50 2,500 14 196 700
50 18 3 150 7,500 54 972 2,700
50 22 1 50 2,500 22 484 1,100
25 22 2 50 1,250 44 968 1,100
    10 600 43,750 184 3,464 10,600

Correlation and Regression Calculations

Correlation and Regression Calculations

Correlation and Regression Calculations

Correlation and Regression Calculations

Correlation and Regression Solution

There is a weak negative correlation.

Correlation and Regression Solution