Respuesta :
Answer:
[tex]r=\frac{6(3750)-(34)(1230)}{\sqrt{[6(256) -(34)^2][6(490500) -(1230)^2]}}=-0.8287[/tex]
So then the correlation coefficient would be r =-0.8287
Step-by-step explanation:
Information provided
Years x 1 3 4 10 9 7
Contribution y 630 180 210 30 90 90
And in order to calculate the correlation coefficient we can use this formula:
[tex]r=\frac{n(\sum xy)-(\sum x)(\sum y)}{\sqrt{[n\sum x^2 -(\sum x)^2][n\sum y^2 -(\sum y)^2]}}[/tex]
For our case we have this:
n=6 [tex] \sum x = 34, \sum y =1230, \sum xy = 3750, \sum x^2 =256, \sum y^2 =490500[/tex]
Replacing into the formula we got:
[tex]r=\frac{6(3750)-(34)(1230)}{\sqrt{[6(256) -(34)^2][6(490500) -(1230)^2]}}=-0.8287[/tex]
So then the correlation coefficient would be r =-0.8287
