Ratio of counts confidence interval

This module calculates confidence intervals for ratios of counts. It is specially designed for environmental indices based on microfossil counts in paleontology, on the form (a+c) / (b+c). This general formula covers the common cases a/b, where c=0, and c / (b+c), where a=0. No data are required in the spreadsheet.

Two methods are provided, as described by Suchéras-Marx et al. (2019). The first is a Monte Carlo procedure based on a transformation of the normal distribution. The second is a straightforward bootstrap, with two versions (simple, which can produce negative values), and percentile. For details see also the Past manual.


Suchéras-Marx, B., Escarguel, G., Ferreira, J. & Hammer, Ø. 2019. Statistical confidence intervals for relative abundances and abundance-based ratios: simple practical solutions for an old overlooked question. Marine Micropaleontology 151:101751.

Published Aug. 31, 2020 7:58 PM - Last modified Aug. 31, 2020 7:58 PM