SOLUTION: Use the equation of the regression line to predict y when x =20 x 5 8 6 10 12 9 ------------------------- y 18 20 15 25 30 25 Please help, Ellen

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Question 150416: Use the equation of the regression line to predict y when x =20
x 5 8 6 10 12 9
-------------------------
y 18 20 15 25 30 25
Please help,
Ellen

Answer by Fombitz(13823) About Me  (Show Source):
You can put this solution on YOUR website!
Find the average x.
x%5Bave%5D=%285%2B8%2B6%2B10%2B12%2B9%29%2F6
x%5Bave%5D=8.33
Find the average y.
y%5Bave%5D=%2818%2B15%2B20%2B25%2B25%2B30%29%2F6
y%5Bave%5D=22.167
For a simple linear regression Y=a%2BbX, use the following formula to find the slope,
b=%28sum%28+%28x-x%5Bave%5D%29%28y-y%5Bave%5D%29+%29%29%2F%28sum%28%28x-x%5Bave%5D%29%5E2%29%29
b=66.666%2F33.333
b=2
a=y%5Bave%5D-bx%5Bave%5D
a=22.167-2%288.333%29
a=22.167-2%288.333%29
a=5.5
drawing%28+300%2C+300%2C-5%2C+25%2C+-5%2C60%2Cgrid%28+1+%29%2C+%0D%0Acircle%285%2C18%2C.1%29%2C%0D%0Acircle%286%2C15%2C.1%29%2C%0D%0Acircle%288%2C20%2C.1%29%2C%0D%0Acircle%289%2C25%2C.1%29%2C%0D%0Acircle%2810%2C25%2C.1%29%2C%0D%0Acircle%2812%2C30%2C.1%29%2C%0D%0Acircle%2820%2C45.5%2C.3%29%2C%0D%0Ablue%28line%280%2C5.5%2C25%2C55.5%29%29+%29
To estimate for x=20
y%2820%29=2%2820%29%2B5.5=45.5