6-1 Mean, Median, Mode and Range
Learn to find the mean, median, mode
and range of a data set.
6-1 Mean, Median, Mode and Range
Vocabulary
mean
median
mode
range
6-1 Mean, Median, Mode and Range
Players on a volleyball team measured how high they could
jump. The results in inches are recorded in the table.
13 23 21 20 21 24 18
One way to describe this data set is to find the mean. The
mean is the sum of all the items divided by the number of
items in the set. Sometimes the mean is also called the
average. The mean of this set of data is the average height
that the vollyball team could jump.
6-1 Mean, Median, Mode and Range
Additional Example 1A: Finding the Mean of a
Data Set
Find the mean of each data set.
Depths of Puddles (in.)
5
8
3
5
4
2
1
mean: 5 + 8 + 3 + 5 + 4 + 2 + 1 = 28 Add all values.
28 ÷ 7 = 4
The mean is 4 inches.
Divide the sum
by the number
of items.
6-1 Mean, Median, Mode and Range
Additional Example 1B: Finding the Mean of a
Data Set
Find the mean of each data set.
Number of Points Scored
96
75
84
7
mean: 96 + 75 + 84 + 7 = 262
Add all values.
Divide the sum
262 ÷ 4 = 65.5
by the number of
items.
The mean is 65.5 points. The average number of
points scored is 65.5.
6-1 Mean, Median, Mode and Range
Check It Out: Example 1A
Find the mean of each data set.
Rainfall per month (in.)
1
2
10
2
5
6
9
mean: 1 + 2 + 10 + 2 + 5 + 6 + 9 = 35 Add all values.
35 ÷ 7 = 5
The mean is 5 inches.
Divide the
sum by the
number of
items.
6-1 Mean, Median, Mode and Range
Check It Out: Example 1B
Find the mean of each data set.
Number of Points Scored
53
26
47
12
mean: 53 + 26 + 47 + 12 = 138
138 ÷ 4 = 34.5
Add all values.
Divide the sum
by the number
of items.
The mean is 34.5 points. The average number
of points scored is 34.5.
6-1 Mean, Median, Mode and Range
Some other descriptions of a set of data are called the
median, mode, and range.
• The median is the middle value when the data are in
numerical order, or the mean of the two middle values if
there are an even number of items.
•The mode is the value or values that occur most often. There
may be more than one mode for a data set. When all values
occur an equal number of times, the data set has no mode.
•The range is the difference between the least and greatest
values in the set.
6-1 Mean, Median, Mode and Range
Additional Example 2: Finding the Mean, Median,
Mode, and Range of a Data Set
Find the mean, median, mode, and range of the data set.
Car Wash Totals
6th Grade
12
7th Grade
11
8th Grade
14
9th Grade
15
mean: 12 + 11 + 14 + 15 = 13
4
Write the data in numerical order. 11, 12, 14, 15
median: 11, 12, 14, 15
12 + 14 = 13
2
mode: none
There are an even number of items,
so find the mean of the two middle
values.
range: 15 – 11 = 4
The mean is 13, the median is 13, there is no mode, and the
range is 4.
6-1 Mean, Median, Mode and Range
Check It Out: Example 2
Find the mean, median, mode, and range of the data set.
Bake Sale Totals
6th Grade
17
7th Grade
11
8th Grade
22
9th Grade
14
mean: 17 + 11 + 22 + 14 = 16
4
Write the data in numerical order.
median: 11, 14, 17, 22
14 + 17 = 15.5
2
mode: none
11, 14, 17, 22
There are an even number of items,
so find the mean of the two middle
values.
range: 22 – 11 = 11
The mean is 16, the median is 15.5, there is no mode, and the
range is 11.