Data Analysis with Microsoft Excel: Updated for Office 2007

I n this chapter you will look at one of the statistical tools used in manufacturing and industry. The proper use of quality con ...

Chapter 12 Quality Control 489 Controlled Variation The reduction of variation in any process is benefi cial. However, you can n ...

Table 12-1 Types of Variation Variation Descriptive Remedy Controlled Variation that is native to the process, resulting from no ...

Chapter 12 Quality Control 491 In contrast, the process depicted in Figure 12-2 is out of control. Both the fourth and the twelf ...

492 Statistical Methods Another common example of a process that is out of control, even though all points lie between the contr ...

Chapter 12 Quality Control 493 the possibility of making errors exists, just as errors can occur in standard hypothesis testing. ...

494 Statistical Methods with subgroup 2 occurring after subgroup 1 and before subgroup 3. As an example, consider a clothing sto ...

Chapter 12 Quality Control 495 n is the number of observations in the subgroup. Note that in this control chart and the charts t ...

496 Statistical Methods Table 12-2 The Teacher Workbook Range Name Range Description Semester A2:A21 The semester of the evaluat ...

Chapter 12 Quality Control 497 If you consider teaching to be a process, with student evaluation scores as one of its products, ...

498 Statistical Methods As you can see from Figure 12-7, no mean score falls outside the con- trol limits. The lower control lim ...

Chapter 12 Quality Control 499 on the shop fl oor by workers who have had little or no formal statistical train- ing (and might ...

500 Statistical Methods A 2 accounts for both the factor of 3 from the earlier equations (used when s was known) and for the fac ...

Chapter 12 Quality Control 501 The weight of the spray in milligrams is recorded, with two observations taken at each of 28 time ...

502 Statistical Methods The lower control limit is 128.336, the average of the subgroup averages is 134.446, and the upper contr ...

Chapter 12 Quality Control 503 Use the information in the Coats workbook to determine whether the range of coating weights is in ...

504 Statistical Methods You might have noticed that the range chart identifi es as out of control a point that was apparently in ...

Chapter 12 Quality Control 505 The range names have been defi ned for the workbook in Table 12-5. Table 12-5 The Accidents Workb ...

506 Statistical Methods Each point on the C chart in Figure 12-12 represents the number of accidents per month. The average numb ...

Chapter 12 Quality Control 507 Figure 12-13 The Steel workbook or 1, a very large subgroup size might be required for the approx ...