Transcript Measures of Central Tendency

Measures of Central Tendency
Mean, Median, and Mode
• Numbers called measures of central
tendency can be used to describe the
center of data. The most common of
these is mean, median, and mode.
Mean
• The mean of a set of data is the sum of
the data divided by the number of items
in the data set.
• Also referred to as the average.
Mean example
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Data set: 4, 1, 5, 2, 2, 4, 2, 4
First add all the numbers together:
4+1+5+2+2+4+2+4= 24
Then divide by the number of items in
the set
• 24 ÷ 8 = 4
• Mean = 4
Median
• The median of a set of data is the
middle number of the data when
ordered from least to greatest.
• If two numbers are in the middle, find
the mean (average) of those two
numbers.
Median Example 1
• Data set: 15, 17, 12, 19, 11
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First order from least to greatest:
11, 12, 15, 17, 19
Then find the number in the middle
Median = 15
Median Example 2
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Data set: 15, 11, 7, 20, 20, 17
First order least to greatest:
7, 11, 15, 17, 20, 20
Two numbers are in the middle - 15 and
17
• Find the mean (average) of the two
• 15 + 17 = 32 ÷ 2 = 16
• Median = 16
Mode
• The mode (or modes) of a set of data is
the number or numbers that occur the
most often.
Mode Example
• EXAMPLE 1:
• Data set: 50, 45, 45, 52, 49, 56, 42
• Mode = 45 (occurs the most often)
• EXAMPLE 2:
• Data set: 29, 34, 27, 29, 34, 19, 38
• Modes = 29 and 34