MedStat Stutter

Phantasies of a physicist fallen among physicians

The title is stolen from Dijkstra.

Papers submitted to medical journals below the top rank are most often reviewed by medical reviewers who have used the Wilcoxon test as a catch-all in their active days. To smuggle a paper though their phalanx, garnish it generously with:

  • p-values
  • Wilcoxon-...

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Excel eignet sich nur eíngeschränkt zur statistischen Auswertung klinischer Studien, aber zu Dateneingabe und Verwaltung bei medizinischen Studienarbeiten ist es durchaus geeignet. Hier einige Rezepte, von Muss sein bis Das Beste zum Schluss.

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Summary

Time series from 13C breath test recordings are used as a surrogate indicator for gastric emptying. Gastric emptying half time t50 is computed by fitting the series with an exponential beta or a Gamma function. Often, records are too short to obtain stable estimates of the trailing part. One can easily get unrealistic emptying times when single curves are fitted (Ghoos et al. (1993), Maes et al. (1998)).

Population methods can come to the rescue. When these fail, Bayesian methods provide a robust approach to non-linear curve fitting.

The methods described here are implemented in packages breathtestcore and breathtestshiny, and can be tested online here

Zipped source files and data

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In einer Studien- oder Bachelorarbeit haben Sie folgende Fragestellung bearbeitet:

Mit physiotherapeutischer Behandlung soll die Kraft im Armmuskel wiederhergestellt werden. Dazu wird bei bei der Eingangsvisite (Visite 0) die Hebekraft mit einer Federwaage gemessen; nach drei Wochen Behandlung w...

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Regression Mysteries

Dieter Menne 15 Juli 2017

In the paper by Hoad et al. (2015), two different methods to measure gastric content volume (GCV) were compared, by MRI and by gamma scintigraphy. A regression line was computed which is the best prediction of GCV(MRI) given GCV(Scintigraphy). The s...

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