Question 739859: In a multiple regression model y' = –13 + 4x1 + 22x2 + 14x3 + 3x4, if the x1 value changes by 2, then the predicted value for y will change by?
I am having a lot of problems with a few different types of these problems. It would really help if you could offer an explanation on how to solve it so I could try the other ones on my own. My teacher wasn't very helpful. Thanks! :)
Answer by jim_thompson5910(35256)   (Show Source):
You can put this solution on YOUR website! y' = –13 + 4x1 + 22x2 + 14x3 + 3x4
z' = –13 + 4(x1+2) + 22x2 + 14x3 + 3x4 ... replace x1 with x1+2, replace y' with z'
z' = –13 + 4x1+8 + 22x2 + 14x3 + 3x4
z' = –13 + 4x1 + 22x2 + 14x3 + 3x4 + 8
z' = (–13 + 4x1 + 22x2 + 14x3 + 3x4) + 8
z' = (y') + 8
z' = y' + 8
So this shows you that y' increases by 8 (to get z')
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Answer:
If x1 increases by 2, then y' increases by 8
Similarly, if x1 decreases by 2, then y' decreases by 8
So overall, if x1 changes by 2, then y' changes by 8
Note: all other input variables are assumed to be fixed.
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