MAD — Grade 7 Accelerated, what it means and where it is taught
Mean absolute deviation — the average distance from the mean; a measure of spread.
Taught in Grade 7 Accelerated.
Where it is taught
What it rests on
Work through these first if this one does not settle.
- Mean — Two kinds of centre: the balance point, and the middle value.
Practise this idea
2 questions in the course bank use MAD, in Sampling, Inferences & Comparing Populations, Centre & Spread.
Problem 1
Class A has mean 84 and MAD 2. Class B has mean 88 and MAD 3. How large is the mean gap relative to the MADs?
- Twice A's MAD and about 1.33 times B's MAD
- Half of each MAD
- Exactly equal to each MAD
Worked answer
Twice A's MAD and about 1.33 times B's MAD
The gap between means is 88-84=4.
Relative to A: 4/2=2 MADs. Relative to B: 4/3≈1.33 MADs.
This describes the separation; it is not a statistical significance test.
Problem 2
Two classes both average 80. Class A has MAD 1.2, class B has MAD 12. Which is true?
- Class B is far more spread out
- They are identical
- Class A is more spread out
- Cannot tell
Worked answer
Class B is far more spread out
Class B has students far from the middle