the set of life - spans of an appliance is normally distributed with a mean $mu = 48$ months and a standard…

the set of life - spans of an appliance is normally distributed with a mean $mu = 48$ months and a standard deviation $sigma = 8$ months. what is the z - score of an appliance that stopped working at 64 months?\n-2\n-1\n1\n2
Answer
Answer:
D. 2
Explanation:
Step1: Recall z - score formula
The z - score formula is $z=\frac{x-\mu}{\sigma}$, where $x$ is the value from the data set, $\mu$ is the mean, and $\sigma$ is the standard deviation.
Step2: Identify given values
We are given that $\mu = 48$ (mean), $\sigma=8$ (standard deviation), and $x = 64$ (the value of interest).
Step3: Substitute values into formula
$z=\frac{64 - 48}{8}=\frac{16}{8}=2$.