Previous authors have combined tests for pairs and unpaired data so that population means can be compared using a paired study design with incomplete data. The primary object of my thesis is to determine the appropriate sample size and the appropriate proportion and configuration of complete data and incomplete data so that a normal approximation can be used to calculate p-values. The test statistic studied is one due to Wilson (1992) in which the sign test and rank sum test are combined to form of composite test statistic.
To fulfill these objectives, the following approach is adopted:
(1) Choose different data scenarios in terms of different sample sizes of paired data and different proportions of complete data.
(2) Obtain the exact sampling distribution of the test statistic under each data scenario we study.
(3) Obtain the normal approximation distribution under each data scenario we study.
(4) Compare the exact and approximate cumulate distribution by their difference on each possible test statistic value.
The results show that when the study groups are approximately balanced with respect to incomplete data, and have at least 9 observations in each group, the normal approximation appears to be useful when the number of complete pairs is as low as 5. However, when the groups are highly unbalanced with respect to incomplete data, using the normal approximation seems not to be appropriate, at least when the total sample size is 70 or less. These results may make public health studies easier to carry out when the data include both complete and incomplete pairs.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-06102005-080906 |
| Date | 08 July 2005 |
| Creators | Yang, Shang-Lin |
| Contributors | Maria Mori Brooks, Vincent C. Arena, John W. Wilson |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-06102005-080906/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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