Averages''

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Averages..

• In table form

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We will start with discrete data

• i.e. the data can only take certain values e.g.
  shoe size

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Number of children in a car
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The mode means .

• most common

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The mode is .

• 1 child per car

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The range is the

• Highest number of children smallest number
  (per car)

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So the range

• 4 0 4

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It is NOT ..

• 9 1 8

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median

• Put in size order
• (Already done in our table)

• Find the middle value

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We have 20 pieces of data

• To find the position of the data value we need.
• Add 1 onto the number of data values 21
• Half this 10½
• We need to look halfway between the 10th and
  11th pieces of data 1 and 1
• So the median is .

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1
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Now for the trickiest bit.

• The mean

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We need to find the total number of children in
the cars

• And then divide by the total number of cars

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Add a column to your table
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Mean number of children per car

• Total No. of children total frequency

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Mean 29 20 ..

• 1.45 children per car

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One for you then
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Mode (most common)

• 0 rings

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Range .

• 4 rings 0 rings 4

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Median

• 100 pieces of data
• Do the add one and half business which leaves
  us looking for the 50½ value (in between the 50th
  and 51st values)
• 50th value is 0 and 51st value is also 0
• So median is 0

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Mean

• New column on table

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Like this
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Mean 45 100

• 0.45

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Heres another one
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Mode .

• 10

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Range

• 12 8 4

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Median

• 50 data values so do the add 1 and half thing
  we want the 25th and 26th values
• Median is 10

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Mean
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Mean

• 498 50 9.96