Asked by y912f

Can someone please show me how to solve this step by step. I'm trying to understand the whole concept but I'm getting confused...

Find the sample linear correlation coefficient between x and y:
x: 5, 2, 2
y: 7, 4, 7
x^2: 25, 4, 4
y^2: 49, 16, 49
xy: 35, 18, 14

I know how to find the correlation coefficient (r), it's SS(xy) / sqr root of SS(x)SS(y)
But when I solve that I get 9....I know r has to be between 0 and 1 so that can't be right at all... Help!
Answered by y912f
Nevermind!

I had SS(x) = 6, and SS(y) = 6, but I kept thinking SS(xy) = 54...I wasn't solving completely. SS(xy) = 3,...so r = .5

Answered by Kuai
sum(x) = 9
Sum(y) = 18
sum(x^2) = 33
sum(y^2) = 114
sum( xy) = 57
n = 3

r = 3(57)-(9)(18)/sqrt(3(33)-9^2)sqrt(3(114)-18^2)

r = (171-162)/sqrt(99-81)sqrt(342-324)

r = 9/sqrt(18)sqrt(18)

r = 9/18 = .5
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