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Geographical Skills

Measures of central tendency

  • 3 things to know
  • All three components

Overview

Mean, median and mode: how each is calculated, what an outlier does to them, and which one a geographer should quote for skewed data such as incomes or house prices.

What you need to know

Answer each one before you reveal it.

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Key term

Name the three measures of central tendency.

Key term

How is the mean calculated?

Numbers

Calculate the mean of 4, 7, 9, 12 and 15.

Questions from this subtopic

Each one with the model answer underneath.

  1. 1

    Name the three measures of central tendency.

    Model answer

    The three measures are the mean, the median and the mode.

  2. 2

    How is the mean calculated?

    Model answer

    The mean is the sum of all values divided by the number of values.

  3. 3

    Calculate the mean of 4, 7, 9, 12 and 15.

    Model answer

    The five values total 47, and 47 divided by 5 is 9.4. The mean is 9.4.

  4. 4

    How is the median found?

    Model answer

    The values are placed in order and the middle one is taken. With an even number of values the mean of the middle two is used.

  5. 5

    State the median of 4, 7, 9, 12 and 15.

    Model answer

    The values are already in order and the middle one is 9. The median is 9.

  6. 6

    Define the mode.

    Model answer

    The mode is the value that occurs most often in a data set. A set may have more than one mode or none at all.

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