# statistics check

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The computer-science aptitude score, x, and the achievement score, y (measured by a comprehensive final), were measured for 10 students in a beginning computer-science course. The results were as follows. (Give your answers correct to two decimal places.)

x 7 10 19 9 20 22 6 13 18 15
y 29 27 28 33 24 15 25 23 21 18

(a) Find the equation of the line of best fit.
y hat = -0.56 + 1.78 x

(b) Find se2.
36.00

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Y hat = -.57x + 32.20

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So what did I do wrong on the part b? That one is wrong also.

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What Do you mean se2

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What Do you mean by this se2

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I am sorry that is Se squared. That is the way it is written on the test.

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SE² is given by:
[ Σ(y-yBar)^2 - [Σ(x-xBar)(y-yBar)]²/Σ(x-xBar)² ] /(n-2)

I get:
Σ(y-yBar)²=258.1
Σ(x-xBar)(y-yBar) = -168.7
Σ(x-xBar)²=296.9
n=10
to get
se²=20.28

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I have a question where did you get 258.1. I must of had my numbers wrong, because I had those other two.

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I got it from summing (y-yBar)^2, and I had yBar=24.3.

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Ok, thank you, I had the wrong numbers for the yBar

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You're welcome!