How Many Bootstrap Replicates Are Necessary?

How Many Bootstrap Replicates Are Necessary?

Phylogenetic bootstrapping (BS) is a standard technique for inferring confidence values on phylogenetic trees that is based on reconstructing many trees from minor variations of the input data, trees called replicates. BS is used with all phylogenetic reconstruction approaches, but we focus here on one of the most popular, maximum likelihood (ML). Because ML inference is so computationally dema...

Bootstrap Tests: How Many Bootstraps?

In practice, bootstrap tests must use a finite number of bootstrap samples. This means that the outcome of the test will depend on the sequence of random numbers used to generate the bootstrap samples, and it necessarily results in some loss of power. We examine the extent of this power loss and propose a simple pretest procedure for choosing the number of bootstrap samples so as to minimize ex...

Classification of emergency department visits: how many are necessary?

In a recent year, hospital emergency departments (EDs) in Rhode Island provided care to over 380,000 patients who did not require subsequent admission to an inpatient or observation bed.1 Many ED visits are for true emergencies that could not be treated in other health care settings, but there has been much discussion among providers, payers, and policy makers on whether some of these patients ...

too many students’ congresses, are they necessary and useful?

How precise do precision tints have to be and how many are necessary?

Among those individuals who habitually wear precision tints, reading speed can vary as a function of the chromaticity of the illuminating light. The reading speed decreases as the chromaticity departs from optimum, whether in saturation or in hue. When the distance in the CIE 1976 UCS diagram between the chromaticity of the illuminating light and that optimal for reading exceeds about 0.08, the...