Answer:
z = 2.75
Step-by-step explanation:
The formula used for z-score is:
[tex]z=\dfrac{x-\mu}{\sigma}[/tex]
where, [tex]\mu[/tex] is the population mean
[tex]\sigma[/tex] is the standard deviation
and x is the value of observation.
Here, x = 135, [tex]\mu[/tex] = 102 and, [tex]\sigma[/tex] = 12
Putting all these values in formula of z-score. We get,
[tex]z=\dfrac{135-102}{12}[/tex]
⇒ z = 2.75
It mean that values have score 2.75 standard deviations above the mean.