Suppose that the average life of a refrigerator before replacement is μ = 15 years with a (68% of data) range from 13 to 17 years. Let x = age at which a refrigerator is replaced. Assume that x has a...

Suppose that the average life of a refrigerator before replacement isμ = 15 years with a (68%
of data) range from 13 to 17 years. Letx = age at which a refrigerator is replaced. Assume
thatx has a distribution that is approximately normal. Find a good approximation for the
standard deviation ofx
values.