Hi qwauck,
The correct answer is that the correlation is undefined.
The correlation coefficient is defined only if the standard deviations of X and Y are finite and non-zero. See Correlation (in statistics - Wikipedia, the free encyclopedia).
Hi,
I got different results for the correlation-coefficient r
x y
----
1 3
2 3
3 3
4 3
Excel returns div/0
TI 84+ returns blank
other programs returns 0.0
my opinion is div/0, because the standard deviation is 0
BUT my maths book has a multiple choice answer : a)-1 b)0 c)1
no div/0 answer possible.
Thanks for reading
Hi qwauck,
The correct answer is that the correlation is undefined.
The correlation coefficient is defined only if the standard deviations of X and Y are finite and non-zero. See Correlation (in statistics - Wikipedia, the free encyclopedia).