Question 16.53

16.53 Response times for telephone repair calls.

A study examined the time required for the telephone company Verizon to respond to repair calls from its own customers and from customers of a CLEC, another phone company that pays Verizon to use its local lines. Here are the data, which are rounded to the nearest hour:

trepair

Verizon
1 1 1 1 2 2 1 1 1 1 2 2
1 1 1 1 2 2 1 1 1 1 2 3
1 1 1 1 2 3 1 1 1 1 2 3
1 1 1 1 2 3 1 1 1 1 2 3
1 1 1 1 2 3 1 1 1 1 2 4
1 1 1 1 2 5 1 1 1 1 2 5
1 1 1 1 2 6 1 1 1 1 2 8
1 1 1 1 2 15 1 1 1 2 2
CLEC
1 1 5 5 5 1 5 5 5 5
  1. Does Verizon appear to give CLEC customers the same level of service as its own customers? Compare the data using graphs and descriptive measures and express your opinion.
  2. We would like to see if times are significantly longer for CLEC customers than for Verizon customers. Why would you hesitate to use a test for this purpose? Carry out a rank test. What can you conclude?
  3. Explain why a nonparametric procedure is appropriate in this setting.
calories h

16.53

(a) The CLEC customers generally have to wait longer than the Verizon customers for repairs. (b) The data are count data and far from normally distributed. , The CLEC customers have systematically higher repair wait times than the Verizon customers. (c) The CLEC group only has two values, 1 and 5. The Verizon group is strongly right skewed and has a large outlier.