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 and standard deviation
, the z-score of a measure X is given by:
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
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.
Less than 3.6 years.