The process of being served at a bank consists of two
independent parts
—
the time waiting in
line and the time it
takes to be served by the teller
.
Suppose that the time waiting
in line has
an expected value of 4 minutes, with a standard
deviation of 1
.
2 minutes, and the time it takes
to be served by
the teller has an expected value of 5
.
5 minutes, with a standard
deviation of
1
.
5 minutes
.
Compute the
a.
expected value of the total time it
takes to be served at the bank
.
b.
standard deviation of the total time it takes to be served at the bank
.