Presentation on theme: "Using TI graphing calculators"— Presentation transcript:
1Using TI graphing calculators Regression tutorialUsing TI graphing calculators
2The regression feature of a graphing calculator can be used to find mathematical models for sets of data.Suppose we want to find a linear equation to model or “fit” the data in this table:8531y42x
3To enter the data Press STAT Select EDIT by pressing ENTER If you already see data listed in the L columns, you must clear it. Click here for directions to clear previous data.
48531y42xTo enter the dataEnter the values of the independent variable in the first column, pressing ENTER after each one. This should be L1
58531y42xTo enter the dataUse the arrow keys to move the cursor to the second column, L2L1 and L2 are called lists.Enter the values of the dependent variable in the second column beside the corresponding numbers in the first column, pressing ENTER after each one.
6Caution!You must have the same number of entries in each column or you will get a DIM MISMATCH error
7To plot the data pointsClear any functions entered in the Y= list or they will be graphed along with your data points.Press STAT PLOT (2nd Y=)Press ENTER2nd MODE(to leave that screen)
8To plot the data pointsMove the cursor to highlight ON and press ENTERIf any settings differ from the ones show on the right, correct them by using your arrow keys
9To plot the data pointsChoose a window to fit the values in your data lists.You can also press ZOOM,#9(STAT)Press GRAPH
10To calculate a regression equation Press STATMove to CALC
11To calculate a regression equation Choose the type of regression you want for your equation. LINREG is for a linear function, EXPREG is exponential, etc.In this example, use the arrow keys to highlight LINREGPress ENTER to select
12To calculate a regression equation Press ENTER againThe calculated numbers for the regression are on the home screenThe regression equation isy = 2.3x – 1.5
13To graph the regression equation You can type in the equation in your Y= menu OR pull it from memory as described below:Follow the procedure to calculate a regression equationPress Y=Press VARSPress #5Move Cursor to EQSelect #1: RegEQ
14To graph the regression equation Press ENTERThis brings the regression equation to Y1
15To graph the regression equation Press GRAPH and you will see the data points as well as the graph of the regression equation.
16To clear data in the stats lists Use the arrow keys to move the cursor on top of the L1 column and press CLEAR (not DELETE).Repeat for L2.Do NOT press DELETE. This will delete the whole column, not just the data. (click here to return to tutorial)
17ReminderBe sure to go back and turn the STAT PLOT off when you are ready to go back to “regular” function graphing.Press 2nd STAT PLOT, press ENTERMove over to highlight OFF and press ENTER again.