OK, I've been trying to figure this problem out for 2 whole days... its tough, at least to me, and its driving me crazy! Any help would be GREATLY appreciated.
From a sample of 10 observations, the following results were obtained:
sum(Yi)=1110
sum(Xi)=1700
sum(XiYi)=205500
sum(Xi^2)=322000
sum(Yi^2)=132100
The r^2 = 0.9758. But, on rechecking these calculations it was found that two pairs of observations were accidentally recorded, Y 90 X 120 and Y 140 X 220 -- instead of -- Y 80 X 110 and Y150 X 210.
Obtain the correct r^2.
...so I can tell that the new Ybar is the same, 111. and the new Xbar will be 168 instead of 170. The original sum(Yi^2) has to be wrong as well as the sum(XiYi) and sum(Xi^2).
How the heck do you do this?! (Not looking for a solution, just some detailed hints if possible.)
Thanks very much for reading!
From a sample of 10 observations, the following results were obtained:
sum(Yi)=1110
sum(Xi)=1700
sum(XiYi)=205500
sum(Xi^2)=322000
sum(Yi^2)=132100
The r^2 = 0.9758. But, on rechecking these calculations it was found that two pairs of observations were accidentally recorded, Y 90 X 120 and Y 140 X 220 -- instead of -- Y 80 X 110 and Y150 X 210.
Obtain the correct r^2.
...so I can tell that the new Ybar is the same, 111. and the new Xbar will be 168 instead of 170. The original sum(Yi^2) has to be wrong as well as the sum(XiYi) and sum(Xi^2).
How the heck do you do this?! (Not looking for a solution, just some detailed hints if possible.)
Thanks very much for reading!
