TI CALCULATOR/CBL TRAINING SESSION

 

Many of you will be familiar with the TI graphing calculators.  In 111 and 112 laboratory this semester we will be using the TI 83 plus calculator and the CBL (Calculator-Based Laboratory unit).  This exercise is to introduce you to the calculator and to one of the data probes. 

 

Introducing the Calculator:

            Examine the face of the TI 83 plus.  Note that each key has multiple uses: the notation on the face of the key, the notation in yellow above the key(reached by first hitting the yellow 2nd key in the upper left), and the notation in green(reached by hitting the green ALPHA key in the upper left).

 

            In these directions the brackets [ ] will be used to indicate a key to be hit.

 

Preparing to Enter Data:

            Turn on the calculator.  The blinking cursor is visible on the screen.

 

            To be sure everyone’s calculator is the same, press [STAT] [5] (set up editor) [ENTER]. 

 

                

 

Clearing the Lists:

            To clear any previous data out of the lists, press [STAT] [4] (clr list) [2nd] L1 [,] [2nd] L2 [ENTER]

 

             

 

Practice Problem:  Information :  A common biological activity involves recording the chirping of crickets at different temperatures, using live crickets.  The data below show the results of such an activity.

            Data:    Temperature (oF)   77   64        81        55        73        58

                                Chirps/min               136        84            148          60            132          65

Entering Data:

            Enter the data listed in the Practice Problem above by pressing [STAT] [1] (edit) 77 [ENTER] 64 [ENTER] 81 [ENTER] 55 [ENTER] 73 [ENTER] 58 [ENTER]

            Arrow over to List 2 and repeat this process with the appropriate data.  Use the à key to move to the top of the second List.

 

                

 

Sorting Data:

            Many times data is collected randomly and sorting is desired.  This is donr by pressing [STAT] [2] (sort A( ) [2nd] L1 [,] [2nd] L2 [ )] [ENTER].  The first list in this command determines the order of the sorting.  The second list comes attached.  The results can be checked by pressing [STAT] [1] (edit).

 

      

 

 

Making a Stat Plot:

            To make a graph from the data you have stored, you will use the Stat Plot button which is located  above the Y= button just below the screen of the calculator.  Press [2nd] Stat Plot 1 (plot 1) [ENTER].  With Plot 1 highlighted, arrow down to ON.  Press [ENTER].  To select the type of graph arrow down to TYPE.  The first TYPE is a scatter plot.  The scatter plot( or xy type graph) is most often used in this course.  Press [ENTER].

            Arrow down to  Xlist which defines the independent variable, e.g., list L1.  Enter list.  Press [ENTER].   Arrow down to Ylist which defines the dependent variable, e.g., list L2.  Enter list.  Press [ENTER].   Arrow down to the last line of the screen and select the symbol for the data points. Press [ENTER]. 

 

Setting the Window (Manually):

            Press [WINDOW] and type in the values shown below or set what you believe to be reasonable ranges.  When finished, press [GRAPH].

 

                       

 

 

Setting the Window (Automatically:  Zoom Stat):

            The calculator can set the optimal window for your data automatically.  Press [ZOOM] and arrow down to 9(zoom stat).  Press [ENTER].  Note:  Zoom stat only works for DATA and not for equations.  This graph looks different because the calculator has chosen a window that maximizes the use of the screen for this data.  Press [WINDOW] to see the X- and Y- ranges chosen by Zoom Stat.

 

      

 

Determining an Equation Automatically:

            Press [STAT] .   Arrow right to CALC and select [4] (LinReg(ax +b)) [2nd] L1 [,] L2 [,]

 

          

 

Transferring  the equation for the line to the Function section of your calculator and checking  the information about the equation for the line:

            Press [VARS], arrow right to Y-VARS and press [ENTER] to select Function.  Press [ENTER] again to select Y1.

   

Now press [ENTER] to perform the linear regression calculation.  Press [ENTER] again to see the linear regression information for the line.  ( a = slope of the line; b = the y intercept of the line.)  Press [GRAPH] to see the results. The line through the data points is the best- fit line determined by the linear regression.

 

        

 

Moving along the Data points vs Interpolating to find predicted values:

                Press [TRACE] and use the à key to move along the data points.    However, to move to any point along the best-fit line, press [TRACE] and the up arrow key.  This will allow you to interpolate the data to any point along the best-fit line (notice the upper right corner of the screen displays P1 when moving from data point to data point and a 1 when moving along the best-fit line.

 

        

 

 

Closing and Clearing:

            Press [2nd] Quit.  Press [Clear].