A major airline surveys passengers to monitor the satisfaction level of its customers. Even though the airline uses a five-point Likert scale (5: outstanding service; 4: good; 3: average; 2: below average; 1: poor), it wants to monitor the proportion that consider the service level as either outstanding or good.
Table shows the number of passengers responding to the survey and the number that consider the service as either outstanding or good. Construct an appropriate control chart and comment on the service level of the airline.
| Table : Passenger Satisfaction Survey in Airline |
| Week |
Number Responded |
Number Checking "Outstanding" or "Good" |
Week |
Number Responded |
Number Checking "Outstanding" or "Good" |
| 1 |
80 |
65 |
14 |
135 |
105 |
| 2 |
110 |
80 |
15 |
125 |
90 |
| 3 |
250 |
210 |
16 |
150 |
118 |
| 4 |
150 |
130 |
17 |
100 |
82 |
| 5 |
90 |
70 |
18 |
110 |
75 |
| 6 |
100 |
85 |
19 |
85 |
64 |
| 7 |
140 |
108 |
20 |
140 |
114 |
| 8 |
220 |
202 |
21 |
165 |
122 |
| 9 |
200 |
184 |
22 |
185 |
148 |
| 10 |
180 |
140 |
23 |
130 |
105 |
| 11 |
70 |
55 |
24 |
125 |
114 |
| 12 |
95 |
70 |
25 |
120 |
105 |
| 13 |
115 |
82 |
|
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