Management is concerned about the quality of the service it provides and wants to establish quality-control limits as a measure for the quality of its tests. Such managerial practice is viewed as significant, because incorrect analysis of a sample can lead to a wrong diagnosis by the physician, which in turn might cost the life of a patient.

For this reason, 100 blood samples were collected at random each day after they had gone through testing. After retesting was performed manually on this sample, the results were:

Month Congestion Incidence January 14 February 18 March 14 April 12 May 16 June 8 July 19 August 12 September 14 October 7 November 10 December 18 144 Part Two Designing the Service Enterprise Day Incorrect Analysis Day Incorrect Analysis 1 8 11 4 2 3 12 6 3 1 13 5 4 0 14 10 5 4 15 2 6 2 16 1 7 9 17 0 8 6 18 6 9 3 19 3 10 1 20 2