Question

Computers from a certain manufacturer have a mean lifetime of 62 months, with a standard deviation of 12 months. The distribution of lifetimes is not assumed to be symmetric. Between what two lifetimes does Chebyshev's Theorem guarantee that we will find at least approximately 75% of the computers

Answer 1

Between 38 and 86 months.

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
`100(1 - (1)/(k^(2)))`.

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.