Equation for best fitting-line?

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tiara

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For b I used the formula : sum(x-xbar)(y-ybar) / sum(x-xbar)^2 and I got -0.44 for the answer

I have no clue on what equation I need to use for step C

Any help is appreciated, Thank you!
 
tiara said:
For b \(\displaystyle \ \ \ \) You mean for part a), right? I used the formula : sum(x-xbar)(y-ybar) / sum(x-xbar)^2 \(\displaystyle \ \ \ \) That is the wrong formula for the correlation coefficient. and I got > > -0.44 < < for the answer \(\displaystyle \ \ \ \) And that is not the correlation coefficient.

I have no clue on what equation I need to use for step C

Any help is appreciated, Thank you!
Click to expand...
Using my TI-83 Plus graphics calculator, I entered the x-values under List 1, and the values in the second row under List 2. I went to the "4: LinReg(ax + b)" option. The display shows "LinReg" and "y = ax + b." Additionally, from reading off the display, \(\displaystyle a \approx \ -0.44, \ \ b \approx \ 94.79, \ \ r^2 \ \approx \ 0.58, \ \ and \ \ r \ \approx \ -0.76.\) \(\displaystyle \ \ \ \ \ \)The correlation coefficient is the value given for r. What you gave, -0.44, is the coefficient for the variable x in the equation of the line of best fit, y = ax + b. I am curious if you are allowed to use technology for any parts of the problem.
 
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