Design-Expert 5.0 Reference Manual - Statease.info

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Central Composite Design Dialog Box - After Selecting 2 Blocks The default selection of “Alpha,” set at 1.68179 in coded units, is the axial distance from the center point and makes the design rotatable. A rotatable design provides equally good predictions at points equally distant from the center, a very desirable property for RSM. You can change alpha to other values via Options. Normally the coded value for alpha exceeds the plus or minus one range of the factorial points, thus pushing the star points outside the factorial box. Therefore, if you enter low and high limits in terms of the factorial portion of the design, you must check the star points to be sure they don’t exceed your operating limits. If you must keep your CCD within specified limits, you will need to check the “Factor ranges entered in terms of alpha” box and then enter the extreme values for each factor. The impact of doing this will be much clearer if you actually click the alpha box and see what happens, then click it again and leave it blank. Do this now. Notice that the ranges change to the more extreme values of the axial points. Click on the Continue button to reach the second page of the “wizard” for building a response surface design. Select 2 from the pull down list for Responses. Then enter the response Name and Units for each response as shown below. At any time in the design-building phase, you can return to the previous page by pressing the Back button. Then you can revise your selections. Completed Response Form Press the Continue button to get the design layout. 6-4 • Response Surface Method (RSM) Tutorials Design-Expert 6 User’s Guide
Save the Data to a File Completed Design Layout (Only partially shown, your run order may be different.) Rev. 3/12/01 The three columns on the left of the design layout identify the experimental runs. Design-Expert will randomize the order, so your runs will probably not match the layout shown above. If you like, adjust the widths of the columns by dragging them with your mouse wherever a double-ended arrow appears on your screen. By right-clicking at the top of a column, you are presented with an option to sort the design by any given variable. The right-click menu also offers an option called Edit Info, which allows you to reformat or change the factor levels. Try it! For example, right-click at the top of Factor 1 (A:time). Notice that you can also change factor names and units of measure. See the on-line Help system for more details on Edit Info and other ways in which you can manipulate the design layout. Now that you’ve invested some time into your design, it would be prudent to save your work. Click on the File menu item and select Save As. Save As Selection Design-Expert 6 User’s Guide Response Surface Method (RSM) Tutorials • 6-5
Page 1 and 2: Section 6 - Response Surface Method
Page 3: Rev. 3/12/01 The default selection
Page 7 and 8: Analyze the Results Design Layout w
Page 9 and 10: Graph of Factor A: Time versus Resp
Page 11 and 12: Rev. 3/12/01 For each source of ter
Page 13 and 14: Rev. 3/12/01 statistical details ne
Page 15 and 16: Rev. 3/12/01 Finally, by scrolling
Page 17 and 18: Rev. 3/12/01 Note that Design-Exper
Page 19 and 20: Contour Plot Rev. 3/12/01 Let’s l
Page 21 and 22: Rev. 3/12/01 Right clicking on a co
Page 23 and 24: Standard Error Plot Rev. 3/12/01 Th
Page 25 and 26: Response Prediction Rev. 3/12/01 No
Page 27 and 28: Design Status Screen Numerical Opti
Page 29 and 30: Rev. 3/12/01 Now click on the secon
Page 31 and 32: Rev. 3/12/01 The program randomly p
Page 33 and 34: Rev. 3/12/01 Design-Expert software
Page 35 and 36: Rev. 3/12/01 Notice that the softwa
Page 37 and 38: Rev. 3/12/01 Click on the solutions
Page 39 and 40: Overlay Plot Rev. 3/12/01 To match
Page 41: Final Comments Rev. 3/12/01 We feel

Design-Expert 5.0 Reference Manual - Statease.info

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