Mean, Median, Mode and Range
Acquire data sets for discrete and continuous numerical variables and calculate the range, median, mean and mode; make and justify decisions about which measures of central tendency provide useful insights into the nature of the distribution of data.
Three ways to say what is typical, and one to say how spread out the data is. Knowing which to use matters more than the arithmetic.
Method
Mean
The balance point. Every value affects it.
Median
The middle value once the data is in order. Order it first, always.
Mode
The most common value. There can be none, one or several.
Range
A measure of spread, not of centre.
Worked example
e.g.
- Put the data in order first.
- Mean: add them and divide by how many.
- Median: take the middle value of the ordered list.
- Mode: find the value that appears most.
- Range: subtract the smallest from the largest.
Practice
Order the data before you do anything else.
1
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2
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3
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4
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5
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