Mean, Median, Mode, and Range

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Mode
Mean
Range
Median
WHAT DO THEY ALL MEAN?
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A number that helps describe a set of data is an
AVERAGE! Sometimes called a MEASURE OF CENTRAL
TENDANCY
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ALL OF THESE ARE AVERAGES

• MEAN
• MEDIAN
• MODE

We use the word the wrong way when we ask a
teacher, Whats my average?
What we should say is, Whats my mean?
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Mean
This is what we usually mean when we say Whats
my average.
We could say, What grade do I normally get?
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How is the mean of a set of numbers found?

• Add all the numbers in the set together.
• Divide the sum by the number of data items in the
  set.
• The quotient is the mean of the set of numbers.
• Example 10, 18, 12 and 16
• Add 10 18 12 16 56
• Divide 56 by 4
• The mean is 14

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Median

• Is the number that is in the middle of a set of
  numbers.
• Half the numbers are below the median and Half
  the numbers are above the median

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How is the median of a set of numbers found?

• Arrange the numbers in the set in order from
  least to greatest.
• The middle number is the median of a set of
  numbers.
• If more than one number is in the middle of the
  set of numbers, the mean of those two numbers is
  the median of the set of numbers.

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Your grades on five tests 95, 87, 92, 100, and 85
Put them in order from least to greatest 85, 87,
92, 95, 100
Your median test grade is 92 half the time you
score below 92 and half the time above 92
The middle number is the median
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Your grades on six tests 95, 85, 87, 92, 100,
and 94
Put them in order from least to greatest 85, 87,
92, 94, 95, 100
The median is the mean of 92 and 94 Or 92 94
186 186 divided by 2 93
The middle is between 2 numbers
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Mode
The number in a data set that occurs most often
Your grades 95, 87, 85, 100, 100 Your mode is
100
Most of the time you get a 100
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How do I identify the mode of a set of numbers?

• Arrange the set of numbers in order from least to
  greatest.
• The number that occurs the most often is the mode
  of that set of numbers.

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You dont have to have a mode. Some data sets
have no mode or no number that occurs more than
others Some might have two modes
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RANGE
Asks the Question How spread out is my data?
Another way to describe data
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How is the range of a set of numbers identified?

• Arrange the numbers in the set in order from
  least to greatest.
• Subtract the lowest number from the highest
  number in the set of numbers.
• The difference of the two numbers is the range of
  a set of numbers.

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Back to your test Scores 95, 87, 92, 100, and 94
Your highest score is a 100 Your lowest score is
87 Your range is 100 87 13 The range 13
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Its Time To Practice!
Number of pets owned by 7 students
2, 1, 1, 4, 3, 2, 1
2
What is the mean
What is the median
2
1
What is the Mode
3
What is the Range
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4 ways to describe data
The Mean what we usually think of as the
average..
The Median The middle number in a data
set..50 of the numbers are above and 50 are
below the median
The Mode The number that occurs most often..
The Range the difference between the smallest
and bigest number..