# A population has a mean of 24.8 and a standard deviation of 4.2. If x_i =19, what is the z-value?

Aug 29, 2017

$z = - 1.38$

#### Explanation:

Given -
Mean $\overline{x} = 24.8$
Standard Deviation $= 4.2$

${x}_{i} = 19$

$z = \frac{x - \overline{x}}{\sigma}$
$z = \frac{19 - 24.8}{4.2} = \frac{- 5.8}{4.2} = - 1.38$
$z = - 1.38$