Hi, out there!

I really need some help/hints on this:

"Suppose a research report is to include 20 confidence intervals, each at the 0.95 level. Although one would expect some relationships, suppose the intervals are based on independent statistics.

a) About how many of the intervals would you expect actually to include the true value of the parameter being estimated?

b) What is the probability that all 20 intervals will contain the true values of the parameters being estimated?"

I've been reading the whole chapter, in my textbook (Berry & Lindgren: Statistics), and I simply can't find it!

Please Help.

Thanks in advance