1. 7a)
1) In order to create a scatter plot of this information open up the table of values
on your graphing calculator by clicking, STAT and then 1:Edit.
2) Plug all the data from the chart given into your graphing calculator with the
“Year” values under L1 starting with 1966 as year 0, and the “Teams” value under
L2.
3) Now click 2ND
and then y= to open up the stat plot menu, click 1 and turn it on.
4) Now hit the GRAPH button and your scatter plot should appear like this. I
have included titles to give it some context.
#ofTeams
Year
2. 7b) Now that you have your graph it is very easy to determine a line or curve of
best fit, using a regression model.
• First turn your diagnostic on by hitting 2nd
and the “0” key, and scrolling down
to diagnostic on. Click enter on “diagnostic on” it will bring you back to the
main screen, hit enter once more so it says “done”. This allows you to see
the R2 value which shows you how well your new model correlates to your
data.
2) Now begin testing which equation to represent our data using regression
models. To start testing which regression model is the best fit for our data
click STAT, scroll over to the right to the CALC menu and use keys 4-0 in
order to test out different equations. I have found that the quadratic model
fits our data best as the R2
value is the greatest.
3. 7c) An equation that can be used to model the given data is:
N(t) = -0.003t2
+ 0.621t + 11.003
Where N is the number of teams and t is the time in years.
*Values in equation are rounded off for simplicity.
This equation is found by using the data given by your regression model in the
previous step:
