BMJ statistical errors

Asymmetric Statistical Errors

Asymmetric statistical errors arise for experimental results obtained by Maximum Likelihood estimation, in cases where the number of results is finite and the log likelihood function is not a symmetric parabola. This note discusses how separate asymmetric errors on a single result should be combined, and how several results with asymmetric errors should be combined to give an overall measuremen...

Errors in the Statistical Analysis

Egri et al. (2012) investigated how the attractiveness of substrates to tabanids (horseflies) varied when painted with different numbers, orientation, and density of stripes. The basic experimental design was a randomized complete block design where the number of flies attracted was counted at regular intervals. The authors analyzed this data using a complete-randomized design ANOVA which is in...

Statistical analysis of timing errors.

Human rhythmic activities are variable. Cycle-to-cycle fluctuations form the behavioral observable. Traditional analysis focuses on statistical measures such as mean and variance. In this article we show that, by treating the fluctuations as a time series, one can apply techniques such as power spectra and rescaled range analysis to gain insight into the mechanisms underlying the remarkable abi...

(Errors in statistical tests)3

In 2004, Garcia-Berthou and Alcaraz published "Incongruence between test statistics and P values in medical papers," a critique of statistical errors that received a tremendous amount of attention. One of their observations was that the final reported digit of p-values in articles published in the journal Nature departed substantially from the uniform distribution that they suggested should be ...

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