An Internet service provider is asking customers to rate it's current
service.  Co. officials are interested in knowing whether people who
have been customers for more than a year are less satisfied than new
customers (less than 6 months).  They use a 5 point scale where 1 =
Extremely staisfied and 5 = Extremely dissatisfied.  The data (already
sorted) are given below:
        Old Customers      New Customers
             1                  1
             2                  1
             3                  1
             3                  1
             3                  1
             3                  2
             3                  2
             4                  3
             5                  4
             5                  4

(a) Create dotplots for each sample.  What assumptions do you think
are reasonable?
(b) Set up the hypotheses to see whether the old customers are less
satisfied than the new customers.
(c) Find the ranks for each data value and the rank sum for each
sample.
(d) At the 0.05 level of significance, what can you conclude?