Question

the ages of commercial aircraft are normally distributed with a mean of 12 years and a standard deviation of 8.2577 years what percentage of individual aircraft have ages between 10 and 16 years assume that a random sample of 64 aircraft is selected and the mean age of the sample is computed what percentage of sample me have ages between 10 years and 16 years

Answer 1

Since the sample is normally distributed we need to use the z score formula:

`Z=(x-\mu)/(\sigma)`

where x is the value we want, mu is the mean and sigma is the deviation.

Now, we need the the probability:

`\begin{gathered} P(10\leq X\leq16)=P((10-12)/(8.2577)\leq Z\leq(16-12)/(8.2577)) \\ =P(-0.2421\leq Z\leq0.4843) \end{gathered}`