Posted by **Ryan St. Laurent** on Thursday, May 24, 2007 at 7:34pm.

I have a question about residual plots and regression equations.

The data is:

X Y

1 6.1

2 5.5

3 9.8

4 10.6

5 14.2

6 21.5

7 29.9

8 37.2

9 50.6

10 64

11 77.6

What function fits this data the best, between Exponential, Linear, Quadratic, and Power.

Also how do you make residual plots on a TI-83 Graphing Calculator?

Thank you so much for your help in advance. This is crucial to my grade.

First, graph it out. what does the graph look like. not straight so toss out Linear. Constantly rising (no humps), so (probably) toss out quadratic. Could be a power function, but offhand id say it was an exponential function (in that the function seems to be growing by e^(ax))

So, next take the natural log of your y values, and graph that. I get something resembling a straight line. Estimate an OLS regression on the logged values. Plot the predicted from the regression, and actual values; the difference between the two are the residuals (which could easily be plotted).