The z-score of an appliance that stopped working at 64 months is 2.
z score is used to determine by how many standard deviations the raw score is above or below the mean. It is given by:
[tex]z=\frac{x-\mu}{\sigma} \\\\where\ x=raw\ score,\mu=mean,\sigma=standard\ deviation\\[/tex]
Given that:
mean = 48, standard deviation = 8 months
For x = 64 months:
[tex]z=\frac{64-48}{8} \\\\z=2[/tex]
The z-score of an appliance that stopped working at 64 months is 2.
Find out more on z-score at: https://brainly.com/question/25638875
