Averages
Single numbers that sum up a set of data. Mean is total divided by count, median is the middle value, mode is the most common, and range is the biggest minus the smallest.
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Analogy
Like asking 'what is typical?' in different ways.
Example
Mean = 30 / 5 = 6Median = 5Mode = 5Range = 9 - 3 = 6
In practice
The mean wage and the median wage can differ if a few people earn a lot.
Practice
Flashcards
- Find the mean, median, mode and range of 3, 5, 5, 8, 9.Mean 6, median 5, mode 5, range 6.
Interview questions
- Find the mean, median, mode and range of 3, 5, 5, 8, 9 and say which suits skewed data.
- Mean = 30 / 5 = 6
- Median = 5 and mode = 5
- Range = 9 - 3 = 6
- The median is less affected by extreme values
Questions people ask
How do you find the median with an even number of values?
Put the values in order, then take the mean of the two middle values. For 2, 4, 6, 8, the middle two are 4 and 6, so the median is 5. With an odd number, it is simply the middle one.
Why might the median be better than the mean?
Extreme values pull the mean up or down, but they barely move the median. In house prices, a few mansions raise the mean a lot. The median shows what a typical house costs more fairly. The mean still matters when every value counts, such as total cost spread evenly across items.