Ranges and Averages

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Ranges and Averages

Appropriate AveragesWhat are appropriate averages? There are 3 methods by which we work out the average, the mean, the median and the mode.

When drawing conclusions we sometimes refer to the one that best suits (or is most appropriate) to your question.

The MODE is the only average you can use for qualitative data (where the answer is expressed as a word). This average tells you which data value is most likely to occur.

The MEDIAN tells you the middle value. Half the data values are greater than the median and half are less than the median.

The MEAN is the only average that takes every value into account. The mean can be affected by very high or very low values. These are sometimes called extreme values.

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KEY QUESTIONS TO GET YOURSELF ORGANISED

It is easy to get yourself confused by so many permuatations……

Is the data grouped or not grouped?

Grouped -> Midpoints x frequencies for mean

Not Grouped -> No midpoints needed, mean = group x frequency

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