Range is the difference
between the greatest and the least numbers in a set of data.
Step 1: 
First
arrange data in order starting with the least number. 
Step 2: 
The
greatest value minus the least value is the
range. 

Example 1:Find the Range

Each
x on the line plot stands for one student. 



0 =
least number 
Books
students read in one month. 
5 =
greatest number 
The
range is the
difference between the least and the greatest number.
5  0 = 5
Range = 5 

Example 2:
Find the Range
Suppose these are the distances you rode your bike for one
week. 

In a list of data,
the difference between the least and the greatest is the
range.

3,
4, 4, 5, 6, 8, 8 
3 =
least number
8 = greatest number 
8  3
= 5
Range = 5 

The
mean
(or average),
is one way to find a number that best represents all the numbers in a
set.
Step 1: 
Find the
sum. 
Step 2: 
Divide the sum by
the number of addends. 

Example

Phil's math grades for one week. 
95 
90 
85 
80 
70 



Suppose Phil's five math grades are 95,
90, 85, 80, 70. To find out his average grade,
follow these steps. 
Step 1: 
Find the sum of the
grades.
95 + 90 + 85 + 80 + 70 =
420 
Step 2: 
Divide the sum by the number
of grades.
420 5
= 84




Remember: Finding Range
First arrange data in order starting with the least number.
The greatest value minus the least value is the
range.

Remember: Finding Mean or Average
(both words are interchangeable)
Step 1 Add the numbers.
Step 2 Count the number of addends.
Step 3 Divide the sum by the number of addends. 
Let's Practice!
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