If three year moving averages for five data items given by 16, 18, 20, 10, 21 are x, y and z respectively, then:

$y < z <x$

The correct answer is Option (3) → $y < z <x$

Given values: $16,\;18,\;20,\;10,\;21$

Three–year moving averages:

$x=\frac{16+18+20}{3}=\frac{54}{3}=18$

$y=\frac{18+20+10}{3}=\frac{48}{3}=16$

$z=\frac{20+10+21}{3}=\frac{51}{3}=17$

The correct choice is: $y < z <x$.