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Spread of Data

Spread of Data

The spread of data is given by the range. The range is the difference between the highest value and the lowest value in a set of data.

A range value will also pick up outliers: that is, those values that are either very high or very low compared to the other values in the set of data.

The range is often used with an average (mean, median, mode) to compare two sets of data. An average gives a likely score, with the range indicating how likely that score will be achieved.

Example 1

What is the range for this set of numbers?

3, 5, 5, 7, 8, 14, 16, 18, 22, 24, 28, 28?

The highest value is 28; the lowest is 3.

Range = highest - lowest = 28 - 3 = 5.

Answer: 25

Example 2

A cricket team scores an average 165 runs, with a range of 83 runs. Another cricket team scores an average 162 runs, with a range of 42 runs. If they play each other, which team is likely to score the highest number of runs?

Although the first cricket team has a slightly higher average, the range of scores means that it is less likely to win the match.

Answer: The second team