Supposeyou measurethe heightand wingspansof nine of your classmatesand gatherthe followingdata.
Use your graphingcalculatorto see if the followingmeasurementsfit this linearmodel(the line ).
Height(inches) Wingspan(inches)We observethat only one of the measurementshas the conditionthat they are equal.Why aren’tmoreof
the measurementsequalto each other?(Answer:The data do not alwaysconformto exactspecifications
of the model.For example,measurementstendto be looselydocumentedso theremay be an error
arisingin the way that measurementsweretaken.)
We enterthe data in our calculatorinL1andL2. We then view a scatterplot. (Caution:note that the data
rangesexceedthe viewingwindowrangeof Changethe windowrangesaccordinglyto include
all of the data,say )
Hereis the scatterplot:
Now let us computethe regressionequation.Sincewe expectthe data to be linear, we will choosethelinear
regressionoptionfrom the menu.We get the equation
In generalwe will alwayswish to graphthe regressionequationover our data to see the goodnessof fit.
Doingso yieldsthe followinggraph,whichwas drawnwith Excel: