We say that is a p-percentile of the distribution F if F( ) = p. Show

We say that ζ is a p-percentile of the distribution F if F(ζ ) = p. Show that if ζ

is a p-percentile of the IFRA distribution F, then F¯(x)  e−θ x , x ζ

F¯(x) e−θ x , x  ζ