To solve the problem we must know about Z-Score.
<h3>What is Z-score?</h3>A Z-score helps us to understand how far is the data from the mean. It is a measure of how many times the data is above or below the mean. It is given by the formula,
Where Z is the Z-score,
X is the data point,
μ is the mean and σ is the standard variable.
The life span of an appliance that has a z-score of –3 is 24 months.
Given to us
- Mean, μ = 48 months,
- standard deviation, σ = 8 months,
- Z-Score = -3
The life span of the appliance can be calculated using the Z-score formula,
Substitute the values,
Hence, the life span of an appliance that has a z-score of –3 is 24 months.
Learn more about Z-score: