Answer:
Between 38 and 86 months.
Step-by-step explanation:
Chebyshev Theorem
The Chebyshev Theorem can also be applied to non-normal distribution. It states that:
At least 75% of the measures are within 2 standard deviations of the mean.
At least 89% of the measures are within 3 standard deviations of the mean.
An in general terms, the percentage of measures within k standard deviations of the mean is given by .
In this question:
Mean of 62, standard deviation of 12.
Between what two lifetimes does Chebyshev's Theorem guarantee that we will find at least approximately 75% of the computers?
Within 2 standard deviations of the mean, so:
62 - 2*12 = 38
62 + 2*12 = 86
Between 38 and 86 months.