The Pacific Northwest (PNW), sometimes referred to as Cascadia, is a geographic region in western North America bounded by the Pacific Ocean to the west and (loosely) by the Cascade Mountain Range on the east.
Mean time between failures (MTBF) describes the expected time between two failures for a repairable system, while mean time to failure (MTTF) denotes the expected time to failure for a non-repairable system. the MTBF is the sum of the operational periods divided by the number of observed failures.
Hi Arash, If you assume a constant rate of failure, then MTTF is the only parameter you need to estimate. Using the exponential distribution you can calculate the reliability at any point in time, R(t)=exp[-t/mttf] Making the assumption of constant failure rate the beta term is 1. If you have time to failure data, then fitting a Weibull to the data is one way to get the estimate of the beta and eta parameters.