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To deselect equations:

  1. Access the list of equations.
    Y= key

  2. Select each equal sign (=).
    arrow down key arrow right key enter key

  3. Continue, until all equations are deselected.

To clear equations:

  1. Access the list of equations.
    Y= key

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

  3. Repeat until all equations are deleted.

To draw default histogram:

  1. Access the ZOOM menu.
    ZOOM key

  2. Select <9:ZoomStat> .
    number 9 key

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

To draw custom histogram:

  1. Access window mode to set the graph parameters.
    window key
    • X min = –2.5
    • X max = 3.5
    • X s c l = 1 (width of bars)
    • Y min = 0
    • Y max = 10
    • Y s c l = 1 (spacing of tick marks on y -axis)
    • X r e s = 1
  2. Access graphing mode to see the histogram.
    graph key

To draw box plots:

  1. Access graphing mode.
    2nd key , [STAT PLOT]

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

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

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

  5. Use the arrows to navigate to <Xlist> .
  6. If "L1" is not selected, select it.
    2nd key , [L1] , enter key

  7. Use the arrows to navigate to <Freq> .
  8. Indicate that the frequencies are in [L2] .
    2nd key , [L2] , enter key

  9. Go back to access other graphs.
    2nd key , [STAT PLOT]

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

The independent variable is "Year," while the independent variable is "Student Ethnic Minority Percent."
Year Student Ethnic Minority Percentage
1970 14.13
1973 12.27
1976 14.08
1979 18.16
1982 27.64
1983 28.72
1986 31.86
1989 33.14
1992 45.37
1995 53.1

Student ethnic minority percentage

This is a scatterplot for the data provided. Year is plotted on the horizontal axis and percent is plotted on the vertical axis. The points show a strong, curved, upward trend.
By hand, verify the scatterplot above.

Note

The TI-83 has a built-in linear regression feature, which allows the data to be edited.The x -values will be in [L1] ; the y -values in [L2] .

To enter data and do linear regression:

  1. ON Turns calculator on.
    on key

  2. Before accessing this program, be sure to turn off all plots.
    • Access graphing mode.
      2nd key , [STAT PLOT]

    • Turn off all plots.
      number 4 key , enter key

  3. Round to three decimal places. To do so:
    • Access the mode menu.
      mode key , [STAT PLOT]

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

    • All numbers will be rounded to three decimal places until changed.
      enter key

  4. Enter statistics mode and clear lists [L1] and [L2] , as describe previously.
    stat key , number 4 key

  5. Enter editing mode to insert values for x and y .
    stat key , enter key

  6. Enter each value. Press enter key to continue.

To display the correlation coefficient:

  1. Access the catalog.
    2nd key , [CATALOG]

  2. Arrow down and select <DiagnosticOn>
    arrow down key ... , enter key , enter key

  3. r and r 2 will be displayed during regression calculations.
  4. Access linear regression.
    stat key arrow right key

  5. Select the form of y = a + bx .
    number 8 key , enter key


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 + 1.617 x
  • Percent = –3176.909 + 1.617 (year #)
The correlation coefficient r = 0.961

To see the scatter plot:

  1. Access graphing mode.
    2nd key , [STAT PLOT]

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

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

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

  6. Navigate to <Xlist> .
  7. If [L1] is not selected, press 2nd key , [L1] to select it.
  8. Confirm that the data values are in [L1] .
    <ON> enter key

  9. Navigate to <Ylist> .
  10. Select that the frequencies are in [L2] .
    2nd key , [L2] , enter key

  11. Go back to access other graphs.
    2nd key , [STAT PLOT]

  12. Use the arrows to turn off the remaining plots.
  13. Access window mode to set the graph parameters.
    window key
    • X min = 1970
    • X max = 2000
    • X s c l = 10 (spacing of tick marks on x -axis)
    • Y min = 0.05
    • Y max = 60
    • Y s c l = 10 (spacing of tick marks on y -axis)
    • X r e s = 1
  14. Be sure to deselect or clear all equations before graphing, using the instructions above.
  15. Press the graph button to see the scatter plot. graph key

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Source:  OpenStax, Introductory statistics. OpenStax CNX. May 06, 2016 Download for free at http://legacy.cnx.org/content/col11562/1.18
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