The life (in hours) of a magnetic resonance imagining machine (MRI) is modeled by a Weibull distribution with parameters
\beta =2
and
\delta
=390
hours. (a) Determine the mean life of the MRI. (Round your answer to 2 decimal places.) (b) Determine the variance of the life of the MRI. (Round your answer to 1 decimal place.) (c) What is the probability that the MRI fails before 250 hours? (Round your answer to 4 decimal places.) (a) (b) (c) i