Please I need help. I need the correct steps how to calculate: Sum $(x-\bar x)(y- \bar y)$?
My numbers are: $x$: 2,4,6,8,10 $y$: 3,5,7,10,12
My results are: $\Sigma x=30$
$\Sigma y=37$
$\bar x= 6$
$\bar y= 7.4$
I think $(x-\bar x)^2$ = 40 and $(y-\bar y)^2$ = 53.38
Standard deviation = 3.16228
Sum of $(x-\bar x)(y-\bar y)^2$)?
Canot figure out what I'm doing wrong? Any help/guide will be appreciated.
When we say $\Sigma (x-\bar x)(y-\bar y)$, you need to calculate $(x-\bar x)(y-\bar y)$ for each data point and add them all up:
$(2-6)(3-7.4)+(4-6)(5-7.4)+(6-6)(7-7.4)+(8-6)(10-7.4)+(10-6)(12-7.4)$
You said: "My results are: X=30 Y=37 Xbar= 6 Ybar= 7.4"
You should have said: "My results are: $\Sigma x=30$, $\Sigma y=37$, $\bar x= 6$, $\bar y= 7.4$"