A mechanical assembly used in an automobile engine contains four major components. The weights of the components are independent and normally distributed with the following means and standard...

A mechanical assembly used in an automobile engine contains four major components. The weights of the components are independent and normally distributed with the following means and standard deviations (in ounces):


(a) What is the probability that the weight of an assembly exceeds 29.5 ounces?
(b) What is the probability that the mean weight of eight independent assemblies exceeds 29 ounces?