Collaborative Statistics by Robert Gallagher - HTML preview

• Continue in the same manner until all data values are entered.

Step 10. In ❬▲✷❪, enter the frequencies for each data value in ❬▲✶❪.

• Type in a frequency and enter it. (If a data value appears only once, the frequency is "1")

,

• Continue in the same manner until all data values are entered.

Step 11. Access statistics mode.

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573

Step 12. Navigate to <❈❆▲❈>

Step 13. Access <✶✿✶✲✈❛r ❙t❛ts>

Step 14. Indicate that the data is in ❬▲✶❪...

, ❬▲✶❪ ,

Step 15. ...and indicate that the frequencies are in ❬▲✷❪.

, ❬▲✷❪ ,

Step 16. The statistics should be displayed. You may arrow down to get remaining statistics. Repeat as neces-

sary.

13.9.3 Drawing Histograms

NOTE: We will assume that the data is already entered

We will construct 2 histograms with the built-in STATPLOT application. The first way will use the default

ZOOM. The second way will involve customizing a new graph.

Step 1. Access graphing mode.

, ❬❙❚❆❚ P▲❖❚❪

Step 2. Select <✶✿♣❧♦t ✶> To access plotting - first graph.

Step 3. Use the arrows navigate go to <❖◆> to turn on Plot 1.

<❖◆> ,

Step 4. Use the arrows to go to the histogram picture and select the histogram.

Step 5. Use the arrows to navigate to <❳❧✐st>

Step 6. If "L1" is not selected, select it.

, ❬▲✶❪ ,

Step 7. Use the arrows to navigate to <❋r❡q>.

Step 8. Assign the frequencies to ❬▲✷❪.

, ❬▲✷❪ ,

Step 9. Go back to access other graphs.

, ❬❙❚❆❚ P▲❖❚❪

Step 10. Use the arrows to turn off the remaining plots.

Step 11. Be sure to deselect or clear all equations before graphing.

To deselect equations:

Step 1. Access the list of equations.

Step 2. Select each equal sign (=).

Step 3. Continue, until all equations are deselected.

To clear equations:

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Step 1. Access the list of equations.

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

Step 3. Repeat until all equations are deleted.

To draw default histogram:

Step 1. Access the ZOOM menu.

Step 2. Select <✾✿❩♦♦♠❙t❛t>

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

To draw custom histogram:

Step 1. Access

to set the graph parameters.

Step 2.

• Xmin = −2.5

• Xmax = 3.5

• Xscl = 1 (width of bars)

• Ymin = 0

• Ymax = 10

• Yscl = 1 (spacing of tick marks on y-axis)

• Xres = 1

Step 3. Access

to see the histogram.

To draw box plots:

Step 1. Access graphing mode.

, ❬❙❚❆❚ P▲❖❚❪

Step 2. Select <✶✿P❧♦t ✶> to access the first graph.

Step 3. Use the arrows to select <❖◆> and turn on Plot 1.

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

Step 5. Use the arrows to navigate to <❳❧✐st>

Step 6. If "L1" is not selected, select it.

, ❬▲✶❪ ,

Step 7. Use the arrows to navigate to <❋r❡q>.

Step 8. Indicate that the frequencies are in ❬▲✷❪.

, ❬▲✷❪ ,

Step 9. Go back to access other graphs.

, ❬❙❚❆❚ P▲❖❚❪

Step 10. Be sure to deselect or clear all equations before graphing using the method mentioned above.

Step 11. View the box plot.

, ❬❙❚❆❚ P▲❖❚❪

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13.9.4 Linear Regression

13.9.4.1 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:

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

Table 13.19: The independent variable is "Year," while the independent variable is "Student Ethnic Minority

Percent."

Student Ethnic Minority Percentage

Figure 13.6: By hand, verify the scatterplot above.

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NOTE: The TI-83 has a built-in linear regression feature, which allows the data to be edited.The

x-values will be in ❬▲✶❪; the y-values in ❬▲✷❪.

To enter data and do linear regression:

Step 1. ON Turns calculator on

Step 2. Before accessing this program, be sure to turn off all plots.

• Access graphing mode.

, ❬❙❚❆❚ P▲❖❚❪

• Turn off all plots.

,

Step 3. Round to 3 decimal places. To do so:

• Access the mode menu.

, ❬❙❚❆❚ P▲❖❚❪

• Navigate to <❋❧♦❛t> and then to the right to <✸>.

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

Step 4. Enter statistics mode and clear lists ❬▲✶❪ and ❬▲✷❪, as describe above.

,

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

,

Step 6. Enter each value. Press

to continue.

To display the correlation coefficient:

Step 1. Access the catalog.

, ❬❈❆❚❆▲❖●❪

Step 2. Arrow down and select <❉✐❛❣♥♦st✐❝❖♥>

... ,

,

Step 3. r and r2 will be displayed during regression calculations.

Step 4. Access linear regression.

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

,

The display will show:

LinReg

• y = a + bx

• a = −3176.909

• b = 1.617

• r2 = 0.924

• r = 0.961