12.4 Notes for the ti-83, 83+, 84 calculator  (Page 2/3)

To deselect equations:

1. Access the list of equations.

   
   

2. Select each equal sign (=).

   
   

3. Continue, until all equations are deselected.

To clear equations:

1. Access the list of equations.

   
   

2. Use the arrow keys to navigate to the right of each equal sign (=) and clear them.

   
   

3. Repeat until all equations are deleted.

To draw default histogram:

1. Access the ZOOM menu.

   
   

2. Select <9:ZoomStat>

   
   

3. The histogram will show with a window automatically set.

To draw custom histogram:

1. Access to set the graph parameters.
2. • $X_{\min }=-2.5$
   • $X_{\max }=3.5$
   • $X_{\mathrm{scl}}=1$ (width of bars)
   • $Y_{\min }=0$
   • $Y_{\max }=10$
   • $Y_{\mathrm{scl}}=1$ (spacing of tick marks on y-axis)
   • $X_{\mathrm{res}}=1$
3. Access to see the histogram.

To draw box plots:

1. Access graphing mode.

   
   , [STAT PLOT]

2. Select <1:Plot 1> to access the first graph.

   
   

3. Use the arrows to select <ON> and turn on Plot 1.

   
   

4. Use the arrows to select the box plot picture and enable it.

   
   

5. Use the arrows to navigate to <Xlist>
6. If "L1" is not selected, select it.

   
   , [L1] ,

7. Use the arrows to navigate to <Freq> .
8. Indicate that the frequencies are in [L2] .

   
   , [L2] ,

9. Go back to access other graphs.

   
   , [STAT PLOT]

10. Be sure to deselect or clear all equations before graphing using the method mentioned above.
11. View the box plot.

    
    , [STAT PLOT]

Linear regression

Sample data

The following data is real. The percent of declared ethnic minority students at De Anza College for selected years from 1970 - 1995 was:

Student ethnic minority percentage

To enter data and do linear regression:

1. ON Turns calculator on

   
   

2. Before accessing this program, be sure to turn off all plots.
   • Access graphing mode.

     
     , [STAT PLOT]

   • Turn off all plots.

     
     ,

3. Round to 3 decimal places. To do so:
   • Access the mode menu.

     
     , [STAT PLOT]

   • Navigate to <Float> and then to the right to <3> .

     
     

   • All numbers will be rounded to 3 decimal places until changed.

     
     

4. Enter statistics mode and clear lists [L1] and [L2] , as describe above.

   
   ,

5. Enter editing mode to insert values for x and y.

   
   ,

6. Enter each value. Press to continue.

To display the correlation coefficient:

1. Access the catalog.

   
   , [CATALOG]

2. Arrow down and select <DiagnosticOn>

   
   ... , ,

3. $r$ and $r^2$ will be displayed during regression calculations.
4. Access linear regression.

   
   

5. Select the form of $y=a+bx$

   
   ,

The display will show:

Linreg

• $y=a+bx$
• $a=-3176.909$
• $b=1.617$
• $r^2=0.924$
• $r=0.961$

This means the Line of Best Fit (Least Squares Line) is:

• $y=-3176.909+1.617x$
• $\mathrm{Percent}=-3176.909+1.617\mathrm{(year\; \#)}$

To see the scatter plot:

1. Access graphing mode.

   
   , [STAT PLOT]

2. Select <1:plot 1> To access plotting - first graph.

   
   

3. Navigate and select <ON> to turn on Plot 1.

   
   <ON>

4. Navigate to the first picture.
5. Select the scatter plot.

   
   

6. Navigate to <Xlist>
7. If [L1] is not selected, press , [L1] to select it.
8. Confirm that the data values are in [L1] .

   
   <ON>

9. Navigate to <Ylist>
10. Select that the frequencies are in [L2] .

    
    , [L2] ,

11. Go back to access other graphs.

    
    , [STAT PLOT]

12. Use the arrows to turn off the remaining plots.
13. Access to set the graph parameters.
    • $X_{\min }=1970$
    • $X_{\max }=2000$
    • $X_{\mathrm{scl}}=10$ (spacing of tick marks on x-axis)
    • $Y_{\min }=-0.05$
    • $Y_{\max }=60$
    • $Y_{\mathrm{scl}}=10$ (spacing of tick marks on y-axis)
    • $X_{\mathrm{res}}=1$
14. Be sure to deselect or clear all equations before graphing, using the instructions above.
15. Press to see the scatter plot.