For the sample x1, x2,…, xn, with mean , the mean absolute deviation is equal to
It is a measure of dispersion but is not often used as variance has preferable algebraic properties.
A measure of spread. For observations x1, x2,…, xn, with sample mean x̄ and median m, the mean absolute deviation about the mean is
and the mean absolute deviation about the median is 
- Ziegler–Nichols tuning
- ZIF socket
- ZigBee
- zig-zag fold
- Zika virus
- Zimbabwe
- Zimmermann note (19 January 1917)
- Zimmerman process
- Zimm–Bragg theory
- zinc
- zincate
- zinc blende
- zinc-blende structure
- zinc chloride
- zinc chloride cell
- zincex process
- zinc finger
- zinc finger nuclease
- zinc group
- zincite
- zinc oxide
- zinc sulphate
- zinc sulphide
- zinc(symbol: Zn)
- zine