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- Mean, median, mode and range
Mean, median, mode and range
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Averages give one typical value for a set of data. The range shows how spread out it is.
The three averages
Mean: add up the values and divide by how many there are.
Median: the middle value when the data is in order. With two middle values, find halfway between them.
Mode: the most common value.
Median: the middle value when the data is in order. With two middle values, find halfway between them.
Mode: the most common value.
Range and outliers
Range = largest value − smallest value. It measures spread.
An outlier is a value that is much bigger or smaller than the rest. It can drag the mean and the range a long way, but hardly moves the median.
An outlier is a value that is much bigger or smaller than the rest. It can drag the mean and the range a long way, but hardly moves the median.
Comparing data
Compare an average (which is typically higher?) and the range (which is more consistent?).
A smaller range means the data is more consistent.
A smaller range means the data is more consistent.
Find the mean, median, mode and range of 4, 7, 7, 9, 13.
- Mean: 40 ÷ 5 = 8
- Median: the middle value is 7
- Mode: 7 appears most
- Range: 13 − 4 = 9
Answer: Mean 8, median 7, mode 7, range 9
Mean: total ÷ how many. Median: middle value in order. Mode: most common. Range: biggest − smallest. Compare data using an average and the range.
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