TI-83 Linear Regression

 

 

Entering Data onto Lists

 

            Recall that you enter data on a LIST, which looks a lot like a spread sheet. Traditionally we enter the data of the independent (controlled) variable on L1 and the dependent (measured) variable on L2

 

                        STAT®Edit   will access the lists.

 

Important Reminders:

·         To remove all the entries from your list, cursor to the top of the list and press Clear.  Do NOT press Delete or it will delete the entire list instead of just the numbers!

·         To replace a deleted list, go to the top of any list and press Insert.  You will then need to name the list.  You may access all the list names by pressing the 2^nd button and the number of the list. (ex: 2^nd ®1 will access L1)  

 

Creating a Stat Plot

 

            To produce a graph of the data, or a plot, you press 2^nd ®Stat Plot and select one of three plots on the summary screen that is displayed.  You will notice that each of the three plots are either on or off.  Select Plot1 by pressing 1, then use your cursor arrows to highlight all of the following options:

                        On Off

                        Type: (Select the first icon)

                       

                        Xlist: L1           (This is the list with the independent variable)

                        Ylist: L2           (This is the list with the dependent variable)

                        Mark:   ð          (This allows you different marks incase you dealing with two

                                                 different sets of data.)

 

           

            Next select Zoom®9 which will automatically set your window to the maximum and minimum points necessary to see your data.  You may not press the Trace button to look at the (x,y) coordinates of each point displayed.

 

Displaying a Linear Regression Line

 

            To calculate a least-squares regression choose Stat®Calc and 4: LinReg(ax+b).

This will place the following command on the Home Screen:

 

                        LinReg (

 

Now enter the names of the lists on which the calculator will perform the regression. For example:  LinReg(L1,L2). NOTE: There is a comma between the list names. The calculator will perform a least-squares regression for you and produce an equation on the home screen.  The calculator can use this equation to produce a line on your Stat Plot if the equation is written in Y=. To copy the equation into Y=, press the following sequence of buttons:

 

                        Y=       VARS        5        EQ        1     GRAPH