Statistics Basics
Grades 6–8 Statistics Data
Data is a pile; statistics are the summary. Four summaries cover most of everyday math:
- Mean — the average: add all, divide by count
- Median — the middle: sort, take the center
- Mode — the most common value
- Range — biggest minus smallest
Data: 4, 7, 7, 8, 12
Mean = (4+7+7+8+12) ÷ 5 = 38 ÷ 5 = 7.6
Median = middle value = 7
Mode = appears twice = 7
Range = 12 − 4 = 8
When the mean lies
Five paychecks: $400, $420, $380, $410, $40,000. Mean = $8,322 — but four of five people earn under $500! One giant value drags the mean. The median ($410) tells the truer story. That's why news quotes median house prices.
Even counts
With an even number of values, the median is the mean of the
middle two: 4, 7, 7, 8 → median (7+7)/2 = 7.
Practice
Mean of 3, 5, 10 = ___
Median of 2, 7, 7, 9, 11 = ___
Mode of 4, 4, 4, 6, 8 = ___
Range of 3, 9, 16 = ___
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