A random sample of size = 16 is selected from a normal popul…

A random sample of size = 16 is selected from a normal population with a mean of 75 and a standard deviation of 8. A second random sample of size = 9 is taken from another normal population with mean 70 and standard deviation 12. Let be the two sample means. Find the probability that exceeds 4.

The time between arrivals of small aircraft at a county airp…

The time between arrivals of small aircraft at a county airport is exponentially distributed with a mean of one hour. Determine the length of an interval of time (in hours) such that the probability that no arrivals occur during the interval is 0.10. What should be the correct R code?

A synthetic fiber used in manufacturing carpet has tensile s…

A synthetic fiber used in manufacturing carpet has tensile strength that is normally distributed with mean 75.5 psi and standard deviation 3.5 psi. Find the probability that a random sample of n = 6 fiber specimens will have sample mean tensile strength that exceeds 75.75 psi.