three questions:

Statstics

Number one:

Let Fi, i = {1, ...,n} be a family of o-algebras on 2. Show that the intersection of all Fi, F = \\\\Fi, (* ) i=1 is also a o-algebra on 2.Assume that the call duration follows an exponential distribution. Find an average call duration, given a probability of 0.3 that the call lasts more than 4 minutes.A random variable Y follows normal distribution with / = 2 and of = 1. Let's define X = 2Y + 3. Calculate: (a) # and of for X, (b) P(X > 8), (c) P(3