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ndltd-OhioLink-oai-etd.ohiolink.edu-ucin11500945862021-08-03T06:11:11Z Goodness-of-Fit Tests for Proportional Odds Model with Gee for Ordinal Categorical Responses & Estimating Sampling Frequency in Pollen Exposure Assessment Over Time Luo, Junxiang Chapter I: In 1994, generalized estimating equations approach (GEE) was extended by Lipsitz, Kim and Zhao to fit the proportional odds model for analyzing repeated (or clustered) ordinal categorical data. However, few methods exist to assess the goodness of fit (GOF) of the fitted models. Four U statistics were proposed in this study to do the GOF test and their performances were evaluated with respect to type I error rates and powers for detecting various model departures by simulation studies and an example illustration. We also compared the proposed U statistics with a Kappa-like classification statistic. Simulation studies show that the proposed U statistics have no obvious difference with each other and perform better than Kappa like classification statistic. All of U statistics provide correct type I error rates very close to the nominal alpha levels and appropriate powers to detect the omission of a quadratic term or an interaction, or the violation of proportional odds assumption. Chapter II: A time series model was fitted to the pollen concentration data collected at Greater Cincinnati area for Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS). A traditional time series analysis and temporal variogram approach were applied to the regularly spaced databases (collected in 2003) and irregularly spaced ones (collected in 2002), respectively. The aim was to evaluate the effect of the sampling frequency on the sampling precision in terms of inverse of standard error of the overall level of mean value across time. The presence of high autocorrelation in the data was confirmed and indicated some degree of temporal redundancy in the pollen concentration data. Therefore, it was suggested that sampling frequency could be reduced from once a day to once every several days without a major loss of sampling precision of the grand mean over time. Considering the trade-offs between sampling frequency and the possibility of sampling bias increasing with larger sampling interval, we recommend that the sampling interval should take values from 3 to 5 days for the pollen monitoring program, if the goal is to track the long-term average. 2006-09-28 English text University of Cincinnati / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=ucin1150094586 http://rave.ohiolink.edu/etdc/view?acc_num=ucin1150094586 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
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NDLTD
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| language |
English
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NDLTD
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| author |
Luo, Junxiang
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Luo, Junxiang
Goodness-of-Fit Tests for Proportional Odds Model with Gee for Ordinal Categorical Responses & Estimating Sampling Frequency in Pollen Exposure Assessment Over Time
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Luo, Junxiang
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| author_sort |
Luo, Junxiang
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| title |
Goodness-of-Fit Tests for Proportional Odds Model with Gee for Ordinal Categorical Responses & Estimating Sampling Frequency in Pollen Exposure Assessment Over Time
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| title_short |
Goodness-of-Fit Tests for Proportional Odds Model with Gee for Ordinal Categorical Responses & Estimating Sampling Frequency in Pollen Exposure Assessment Over Time
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| title_full |
Goodness-of-Fit Tests for Proportional Odds Model with Gee for Ordinal Categorical Responses & Estimating Sampling Frequency in Pollen Exposure Assessment Over Time
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| title_fullStr |
Goodness-of-Fit Tests for Proportional Odds Model with Gee for Ordinal Categorical Responses & Estimating Sampling Frequency in Pollen Exposure Assessment Over Time
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| title_full_unstemmed |
Goodness-of-Fit Tests for Proportional Odds Model with Gee for Ordinal Categorical Responses & Estimating Sampling Frequency in Pollen Exposure Assessment Over Time
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| title_sort |
goodness-of-fit tests for proportional odds model with gee for ordinal categorical responses & estimating sampling frequency in pollen exposure assessment over time
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| publisher |
University of Cincinnati / OhioLINK
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| publishDate |
2006
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| url |
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1150094586
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| work_keys_str_mv |
AT luojunxiang goodnessoffittestsforproportionaloddsmodelwithgeeforordinalcategoricalresponsesestimatingsamplingfrequencyinpollenexposureassessmentovertime
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1719432392214577152
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