Question

In a distribution where X=21 and S=3, what is the z-score?
Answer and rationalization:

Answer 1

$Z = \frac {X-M} {S}$

$Z = \frac {21-M} {3}$

Assume M = 20

then Z score

$Z = \frac {21-20} {3}=0.33$

Z(0.33) = 0.62930