Transcript Mean Mode Median

Section 5.7
Decimal Applications:
Mean, Median, and Mode
Measures of Central Tendency
The mean, the median, and the mode are
called measures of central tendency. They
describe a set of data, or a set of numbers,
by a single “middle” number.
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Mean (Average)
The most common measure of central
tendency is the mean (sometimes
called the “arithmetic mean” or the
“average”).
The mean (average) of a set of number
items is the sum of the items divided
by the number of items.
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Finding the Mean
Find the mean of the following list of
numbers.
2.5
5.1
9.5
6.8
2.5
Continued.
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Finding the Mean
The mean is the average of the
numbers:
2.5
2.5 + 5.1+ 9.5 + 6.8 + 2.5
5.1
5
9.5
= 5.28
6.8
2.5
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Median
You may have noticed that a very low
number or a very high number can
affect the mean of a list of numbers.
Because of this, you may sometimes
want to use another measure of central
tendency, called the median.
The median of an ordered set of numbers is
the middle number. If the number of items is
even, the median is the mean (average) of
the two middle numbers.
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Finding the Median
Find the median of the following list of
numbers.
2.5
5.1
9.5
6.8
2.5
Continued.
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Finding the Median
List the numbers in numerical order:
2.5
2.5
Median
5.1
6.8
9.5
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Helpful Hint
In order to compute the median, the
numbers must first be placed in order.
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Mode
The mode of a set of numbers is the
number that occurs most often. (It is
possible for a set of numbers to have
more than one mode or to have no
mode.)
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Finding the Mode
Find the mode of the following list of
numbers.
2.5
5.1
9.5
6.8
2.5
Continued.
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Finding the Mode
List the numbers in numerical order:
2.5
5.1
The mode is 2.5.
9.5
6.8
2.5
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Helpful Hint
Don’t forget that it is possible for a list
of numbers to have no mode. For
example, the list
2, 4, 5, 6, 8, 9
has no mode. There is no number or
numbers that occur more often than
the others.
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