Weibull Reliability Distribution

[Ricardo Silva]

Suppose I know that the mean life of a machine follows a Weibull 2-parameter distribution.
If I look to n machines, which operates independently, how I can found the distribution function of the conjointly mean life?

[Anonymous]

The parameters of the Weibull distribution are also distributed so the mean life function would be distributed based on the parameters. Now you want to the distribution of a conjoint mean life that is a function of the parameters? What exactly are you trying to do?