The ages of commercial aircraft are normally distributed with a mean of 13.5 years and a standard deviation of 7.9013 years. What percentage of individual aircraft have ages between 10years and 16 years? Assume that a random sample of 81 aircraft is selected and the mean age of the sample is computed. What percentage of sample means have ages between 10 years and 16 years?

The percentage of individual aircraft that have ages between 10 years and 16 years

The percentage of sample means that have ages between 10 years and 16 years is

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