Authors: | Kunert, Joachim Wilk, Adrian |
Title: | Unreplicated fractional factorials, analysis with the half-normal plot and randomization of the run order |
Language (ISO): | en |
Abstract: | There is an ongoing discussion whether it is wise to randomize the run order of a factorial experiment if there is concern about a possible time trend in the experiment. It can be argued that a randomized order is not very effective because the trend inflates the error. Some authors even criticize that a randomized order will normally not be orthogonal to trend, they claim that therefore there will be bias under the randomized order. On the other hand, a systematic order will only be useful if the true trend is behaving as is predicted by the model. The present paper investigates the properties of different run order strategies in a simulation study with unreplicated factorial designs. We check to which extend the presence of a time trend might inflate the probability of false rejection of a true nullhypothesis, and we compare the power of significance tests based on the half-normal plot under the various run order concepts. |
Subject Headings: | Half-normal plot Time trend Unreplicated factorial designs Randomization |
URI: | http://hdl.handle.net/2003/29121 http://dx.doi.org/10.17877/DE290R-2175 |
Issue Date: | 2011-09-29 |
Appears in Collections: | Sonderforschungsbereich (SFB) 823 |
Files in This Item:
File | Description | Size | Format | |
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DP_3811_SFB823_Kunert_Wilk.pdf | DNB | 357.48 kB | Adobe PDF | View/Open |
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