#4946 Maths Assignment

Exercises 297

r:; Using the following data, prepare a run chart, scatter chart, and control chart. A late surgery is defined as any surgical operation that was started more than 30 _minutes after its scheduled time Table 14-4). The ambulatory healt~ · experiencing an increased '·, number of student complaints concerning the services it offers in its walk- "\

11 in urgent care clinic.

The Basis of Complaint

Type 1 The quality of service received Type 2 Waiting time was too long Type 3 Follow-up care was not available Type 4 Clinic was hard to find in the building

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Type 5 The medical care/treatment took too long Type 6 · They could not find my medical record

Using these data, select a complaint for analysis. Your analysis must include a fish bone chart as well as other types of charts and techniques you deem neces- sary to appropriately analyze this data (Table 14-5). What do you recommentj/

) --.and why? //

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294 CHAPTER 14: QUALITY ANALYSIS

Table 14-4 Number of Late Surgeries

Month Number of Surgeries Number of Late Surgeries

January 435 112

February 401 129

March 572 186

April 409 103

May 577 89

June 329 67

July 467 156

August 301 94

September 235 89

October 325 127

November 378 156

December 444 124

Total 4873 1432

In March the number of medically complicated births was 20. The moving range, expressed as an absolute number, for February-March is the absolute difference or 7, not -7. A chart can be used to examine the moving ranges, the month-to-month variation that may be occuuing.

Calculate the moving range by time interval (e.g., month), sum the differences, and then divide this sum by the number of range calculation. In the example, divide by 11 to determine the average moving range. For the example, the average.moving range is 5,5 births.

The upper control limit for a moving range chart (of individual values) is the average moving range X 3.27-3.27 is a constant,just as 1.96 is the constant used to calculate a 95% confidence interval when we use the central limit theorem.

In our example, therefore, the upper control limit for the moving range chart is:

Average Moving Range = 5.5 X (the constant) 3.27 = 17.985

For this control chart, 17 .985 is the upper threshold limit used to evaluate the variation presented in the time series analysis we have been using involving medi- cally complicated births. It is the upper boundary or control limit. Given the nature of this chart there is no lower limit.