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:
the mean or average 

the sum of all data 

the sum of the squares 

the sample standard deviation 

the population standard deviation 

the number of elements 

the minimum element 

the first quartile 

the median of the data 

the third quartile 

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 1Var STATS by pressing ENTER. Press 2nd 1 to type and 2nd 2 to type .
After pressing ENTER again, the final screen should appear as shown below:
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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