Answer :
Answer:
Less than 3.6 years.
Step-by-step explanation:
Normal Probability Distribution
Problems of normal distributions can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
Mean of 5.8 years, and standard deviation of 1.7 years.
This means that [tex]\mu = 5.8, \sigma = 1.7[/tex]
The 10% of items with the shortest lifespan will last less than how many years?
Less than the 10th percentile, which is X when Z has a p-value of 0.1, so X when Z = -1.28.
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]-1.28 = \frac{X - 5.8}{1.7}[/tex]
[tex]X - 5.8 = -1.28*1.7[/tex]
[tex]X = 3.6[/tex]
Less than 3.6 years.