Yang, Shang-Lin
(2005)
EVALUATION OF THE NORMAL APPROXIMATION FOR THE PAIRED TWO SAMPLE PROBLEM WITH MISSING DATA.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
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.
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Details
| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
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| ETD Committee: |
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| Date: |
8 July 2005 |
| Date Type: |
Completion |
| Defense Date: |
7 June 2005 |
| Approval Date: |
8 July 2005 |
| Submission Date: |
10 June 2005 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
School of Public Health > Biostatistics |
| Degree: |
MS - Master of Science |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Choice of Criterion; Test Statistic T1 |
| Other ID: |
http://etd.library.pitt.edu/ETD/available/etd-06102005-080906/, etd-06102005-080906 |
| Date Deposited: |
10 Nov 2011 19:46 |
| Last Modified: |
15 Nov 2016 13:44 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/8060 |
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