The big idea
⚖️
"Average" names three different things
And which one is quoted can reverse a headline.
Statistics for Everyday Life · Lesson 4
Averages and Distributions
beginner⏱ 17 min · 7 cards
Try it
Which Average?
“Total payroll cost for next year, from 200 salaries.”
Which summary honestly answers the question?
Pick the summary that answers each question honestly.
Compare
Ten salaries, two answers
Mean
£50,000
Tap.
tap for example ↻
Median
£27,500
Tap.
tap for example ↻
For total payroll cost the mean is right. For "what would I earn" it is close to a lie.
Key term
A free diagnostic
What does a large mean-median gap tell you?
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Skew
A tail. The mean has been pulled toward extreme values and is no longer describing a typical case.
Nuance
One graduate
Maester Note
A university’s geography graduates once topped salary rankings. Michael Jordan had graduated from the programme. The mean was computed correctly and was useless.
Quick check
What makes statistics necessary?
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