This is a problem of control charts Sampl Number of Dissatisfied e Patients 1 6 2 3 3 10 4 7 5 2 6 9 7 11 8 7 9 6 10 6 11 5 12 3 13 2 14 8 15 12 16 8 Mean = 6.5625 Standard deviation = 3.076 These have determined using formulae in Excel Following are the out of control signals: A single point outside the control limits. In Figure 1, point sixteen is above the UCL (upper control limit). Two out of three successive points are on the same side of the centerline and farther than 2from it. In Figure 1, point 4 sends that signal. Four out of five successive points are on the same side of the centerline and farther than 1from it. In Figure 1, point 11 sends that signal. A run of eight in a row are on the same side of the centerline. Or 10 out of 11, 12 out of 14 or 16 out of 20. In Figure 1, point 21 is eighth in a row above the centerline. Obvious consistent or persistent patterns that suggest something unusual about your data and your process. Since none of the above signals are present, the process is in control Thirty patients who check out of the Rock Creek County Regional Hospital each week are asked to complete a questionnaire about hospital service. Since patients do not feel well when they are in the hospital, they typically are very critical of the service. The number of patients who indicated dissatisfaction of any kind with the service for each 30patient sample for a 16-week period is as follows: .:. Construct a control chart to monitor customer satisfaction at the hospital using 3 limits and determine if the process is in control. SOLUTION: p 105 0.22 30 16 p 1 p n 0.22 3 0.0756 UCL p 3 0.447 LCL 0.22 3 0.0756 0.216 Although the process appears to be in control, the average proportion of \"defects'' among leaving patients, p=0.22 seems high and the hospital should probably adopt some quality improvement measures