Linear Modeling<br />Ok...grab a TI and follow along with the problem:<br />
The number of women practicing law has increased substantially in the last four decades. Use a graphing calculator and the data in the table to:<br />Make a scatter plot of the data.<br />Find the equation of the line of best fit.<br /> Predict the percent of lawyers who will be women in 2010.<br />
Before we do anything you have to enter the data. Go to STAT --> Edit and hit enter. Put the first column in for L1 and the second column in L2. If there is data already there you can either delete by highlighting and hitting 'DEL' or hitting 'clear' and rewriting over it or just hit enter to leave it blank.<br />
When all the data is in, it should look like this:<br />Just hit 2nd --> Mode to go back the main screen to save it. Now, we can start the problem.<br />
To graph it on the calc, hit 2nd --> y = to open <br />the 'STAT PLOT' menu. <br />Highlight 1: and hit enter to go to sub screen. <br />Move the cursor on to 'ON' and hit enter. <br />You'll see the 'ON' is now highlighted. <br />Now hit graph. <br />To make a scatter plot you can either sketch it by hand or use your TI<br />
It may or may not appear depending on the data. To fix that, hit Zoom --> 9: ZoomStat. It should come up like this:<br />
To find the line of best, go back to the main screen. (by hitting 2nd--> Mode) <br />Then select Stat --> <br />Calc --> <br />8: LnReg (a + bx). <br />This will come up on the main screen. <br />Hit enter to run the program. <br />You're result will look like…………………….<br />
Depending on your calculator settings, you may or may not see 'r' or you may see 'r' and r2.To set the calc to show r and r2, go to 2nd --> 0. This will pull up the catalog. Scroll all the way down to DiagnosticOn and hit enter<br />
So the equation for the line of best fit y = .059x - 104.51. As a side note, the correlation is a .25 which is terrible!!<br />To predict what percent of women lawyers there <br />will be in 2010, plug 2010 in for x and simplify. <br />Your answer will be about 14.08%, but judging by the <br />low correlation, this probably isn't a very good estimate<br />
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