Unplanned shutdowns of reactors have been a chronic problem. After much discussion, the consensus-called the "wisdom"-identified "cylinder changes" and "human error" as the primary causes. A diagnostic approach based on facts was instituted. Here are data on the causes of previous shutdowns:
|
Cause
|
Frequency
|
|
Cylinder changes
|
21
|
|
Human error
|
16
|
|
Hot melt system
|
65
|
|
Initiator system
|
25
|
|
Interlock malfunction
|
19
|
|
Other
|
23
|
|
169
|
(a) Convert the preceding data into a Pareto table having three columns: cause, frequency, and percentage of total frequency.
(b) Calculate the cumulative frequencies for the table in part (a).
(c) Calculate the percentage cumulative frequencies. Make a Pareto diagram by plotting percentage cumulative frequency versus causes.
(d) Comment about the wisdom versus the fact.