Quick Links In August we examined how to compare two processes. Sometimes you will need to compare more than two processes. For example, you might be comparing the products produced by three different shifts or from three sister plants. The question is, "Are the processes making the same product?
This technique represents a snapshot in time for the two processes. You cannot be sure of obtaining similar results in the future unless the processes are in statistical control. Comparing the Variances The approach used below to construct a confidence interval for the difference in two averages assumes that the variation is consistent between the two processes, i.
This must be checked. To determine if two variances are the same, the F distribution is used. To calculate the F value based on sample results, the larger sample variance is divided by the smaller sample variance. The table values of F depend on two degrees of freedom.
Many statistical books contains the F tables. This gives the critical value of F for a given confidence coefficient and the two degrees of freedom. If the calculated value of F is larger than the table critical value, it is concluded that there is a difference in the two variances.
If the calculated value is less than the table value, it is concluded that there are no differences in the two variances. Once it has been determined that the variation is consistent between the two processes, the confidence interval for the difference between the two averages can be constructed.
Estimating the Variance The next step is to estimate the variance. If the variances are not the same between the two processes, you can not use this method. There are two estimates of the variance from the sample variances. These are pooled to get a single estimate of the variance. The pooled variance is given by the equation: The square root of the pooled variance is a measure of the part-to-part variation or the process standard deviation using information from both samples.
Difference in Two Averages The pooled variance is used to help estimate the standard deviation, sdiff, which estimates the variation of differences in two sample averages.
The value of t can be found in the t tables of many statistics books. If the confidence interval does not contain zero, it is concluded that the two processes are operating at different averages.
If the confidence interval does contain zero, you conclude that there is no evidence that the two processes are operating at different averages. They appear to have the same average. Example In a plant, two different reactors are making the same product.
The question was asked if the reactors produce the same yield. The data below were collected. Is there a difference in the yield from the two reactors? The first step is to calculate the average and variance for each of the reactors.
The variance is the square of the standard deviation.Comparing Business Process Variants using Models and Event Logs J.C.A.M. Buijs 1and H.A. Reijers;2 1 Eindhoven University of Technology, The Netherlands initiativeblog.com,[email protected] 2 Perceptive Software, The Netherlands Abstract.
Organizations realize that bene ts can be achieved by closely working together on the . Business Process Management Software (or BPM Software) is the common name for computer systems designed to review corporate performance, and to distinguish the best practices for a company to reach its goals.
Two Processes; Comparing the Variances; Estimating the Variance; Difference in Two Averages; Example; Summary; Quick Links; Sometimes you will need to compare two processes.
For example, you might be comparing the products from two different suppliers or from two sister plants. You might be comparing two ways of processing invoices. Oracle Business Process Management, a member of the Oracle Business Process Management Suite, is a complete set of tools for creating, executing, and optimizing business processes.
The suite enables unparalleled collaboration between business and IT to automate and optimize business processes.
PowerPoint Comparison Template showing Positives and Negatives. Description: Here are 30 variations of PowerPoint comparison chart templates. The variations of the diagram graphic include PowerPoint pros and cons template, Positives and Negatives evaluation chart template, two different views of an event, two sides of an argument, .
Comparing Business Process Variants using Models and Event Logs J.C.A.M. Buijs 1and H.A. Reijers;2 1 Eindhoven University of Technology, The Netherlands initiativeblog.com,[email protected] 2 Perceptive Software, The Netherlands Abstract. Organizations realize that bene ts can be achieved by closely working together on the design of their business processes.