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1NAMILL
11-18-2005, 08:42 PM
I'm having a little trouble with the following question:

Four pairs of data yield r = 0.942 and the regression equation (predicated value of y =3x. Also, the mean of y=12.75. What is the best predicted value of y for x=2.6?

Can you help? I'm not sure what formula to use. I'm trying to figure out if I'm suppose to use the regression equation. However, I don't know how to find the slope and y-intercept.

Thanks,

JohnM
11-18-2005, 09:07 PM
If the predicted value of y = 3x, then for x=2.6, y = 3*2.6 = 7.8

If in fact y=3x is the regression equation, then the slope = 3, and y-intercept=0

(in general, the regression equation is y = b + ax, with y-intercept b and slope a)

1NAMILL
11-19-2005, 08:56 AM
John,
Thanks, I got 7.8. However, I'm still not sure what formula to use. In the question it gives r = 0.942 and the mean of y to be 12.75. How do I incorporate thoses values in the equation since the predicted value of y is now 7.8?

JohnM
11-19-2005, 10:58 AM
Now I'm a bit confused about what the question is asking for....:)

Could you post exactly how the entire question is worded?

Thanks,
John

1NAMILL
11-19-2005, 12:41 PM
Here is the question again:

Four pairs of data yield r = 0.942 and the regression equation (predicted value of y =3x. Also, the mean of y=12.75. What is the best predicted value of y for x=2.6?

JohnM
11-19-2005, 01:55 PM
The best predicted value of y for x=2.6 is 3*2.6 = 7.8

Sometimes they will give you irrelevant info in the question to see if you can cut through the nonsense and answer the question.....

1NAMILL
11-19-2005, 09:10 PM
Thanks John. I got confused with all the extra stuff.