984 resultados para Medical statistics
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Cover title.
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At head of title: Department of Commerce and Labor. Bureau of the Census. W.M. Steuart, director.
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Mode of access: Internet.
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"Prepared by Theodore A. Janssen, chief of the Nosology section."--p.1.
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Hearings held Oct. 1, 1953-Jan. 11, 1954.
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Later ed. published under title: An arithmetical and medical analysis of the diseases and mortality of the human species.
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Funding No funding was received for this study. Acknowledgements We would like to acknowledge the help and expertise provided by Fiona Chaloner who performed the data linkage and extraction from the databases. We also thank the medical statistics team, University of Aberdeen, and in particular Dr Lorna Aucott, for their advice on the analysis of the data. We would also like to thank Margery Heath for proofreading and formatting the paper.
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Funding No funding was received for this study. Acknowledgements We would like to acknowledge the help and expertise provided by Fiona Chaloner who performed the data linkage and extraction from the databases. We also thank the medical statistics team, University of Aberdeen, and in particular Dr Lorna Aucott, for their advice on the analysis of the data. We would also like to thank Margery Heath for proofreading and formatting the paper.
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Given an observed test statistic and its degrees of freedom, one may compute the observed P value with most statistical packages. It is unknown to what extent test statistics and P values are congruent in published medical papers. Methods: We checked the congruence of statistical results reported in all the papers of volumes 409–412 of Nature (2001) and a random sample of 63 results from volumes 322–323 of BMJ (2001). We also tested whether the frequencies of the last digit of a sample of 610 test statistics deviated from a uniform distribution (i.e., equally probable digits).Results: 11.6% (21 of 181) and 11.1% (7 of 63) of the statistical results published in Nature and BMJ respectively during 2001 were incongruent, probably mostly due to rounding, transcription, or type-setting errors. At least one such error appeared in 38% and 25% of the papers of Nature and BMJ, respectively. In 12% of the cases, the significance level might change one or more orders of magnitude. The frequencies of the last digit of statistics deviated from the uniform distribution and suggested digit preference in rounding and reporting.Conclusions: this incongruence of test statistics and P values is another example that statistical practice is generally poor, even in the most renowned scientific journals, and that quality of papers should be more controlled and valued
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Mode of access: Internet.
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Mode of access: Internet.
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Provisional Circ record
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For many decades correlation and power spectrum have been primary tools for digital signal processing applications in the biomedical area. The information contained in the power spectrum is essentially that of the autocorrelation sequence; which is sufficient for complete statistical descriptions of Gaussian signals of known means. However, there are practical situations where one needs to look beyond autocorrelation of a signal to extract information regarding deviation from Gaussianity and the presence of phase relations. Higher order spectra, also known as polyspectra, are spectral representations of higher order statistics, i.e. moments and cumulants of third order and beyond. HOS (higher order statistics or higher order spectra) can detect deviations from linearity, stationarity or Gaussianity in the signal. Most of the biomedical signals are non-linear, non-stationary and non-Gaussian in nature and therefore it can be more advantageous to analyze them with HOS compared to the use of second order correlations and power spectra. In this paper we have discussed the application of HOS for different bio-signals. HOS methods of analysis are explained using a typical heart rate variability (HRV) signal and applications to other signals are reviewed.