Evaluating the statistical properties of Cohen’s κ, this thesis conducts a study of the reliability of patient surveys and medical records for mild cases of Covid-19. Using data collected from Uppsala University Hospital, right-tailed hypothesis testing is performed for the variables Hypertension, Lung disease, Fatigue, Dyspnea and loss of smell and/or taste. Results show only Hypertension rejecting the null hypothesis of low reliability, thus achieving a "Moderate" strength of agreement according to Landis and Koch. Simulating 10000 draws of a multinomial distribution, the thesis finds that the distribution of κ is asymmetric. Simulation of the size-adjusted power of κ shows that the probability of committing Type II errors is significant for the sample sizes of 400 and lower used in the study. In addition, κ appears vulnerable to the effects of sample bias and prevalence and thus risk giving a misleading result. As such,researchers should compare it with the adjusted estimator PABAK if possible.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:uu-477008 |
| Date | January 2022 |
| Creators | Kock, Claes |
| Publisher | Uppsala universitet, Statistiska institutionen |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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