Consider the following frequency distribution for grouped data:
Class |
Frequency |
Midpoint |
5.5 - 10.5 |
1 |
8 |
10.5 - 15.5 |
2 |
13 |
15.5 - 20.5 |
3 |
18 |
20.5 - 25.5 |
5 |
23 |
25.5 - 30.5
|
4 |
28 |
30.5 - 30.5 |
3 |
33 |
30.5 - 40.5 |
2 |
38 |
The ONE VARIABLE STATISTICS option provides summary information on a frequency distribution of grouped data. Specifically, the following information is provided:
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the mean or average |
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the sum of all data |
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the sum of the squares |
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the sample standard deviation |
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the population standard deviation |
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the number of elements |
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the minimum element |
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the first quartile |
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the median of the data |
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the third quartile |
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the maximum element |
First enter the midpoints into
and frequencies into
.
To learn how to enter data into a list, go to Making
a Table . Once the data are entered, the screen should appear as shown
below:
Next, press STAT and then press the RIGHT ARROW to get to the CALC menu. Select 1-Var STATS by pressing ENTER. Make sure L1 listed for List: the pre ENTER to FreqList: and press 2nd 2 to type L2. Press ENTER twice.
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After pressing ENTER again, the final screen should appear as shown below:
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The
located at the bottom left of the screen indicates that there are more entries
to be displayed. By pressing the DOWN ARROW key, the other ONE
VARIABLE STATISTICS are displayed.
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