Showing papers by "R. W. Payne published in 1977"

A General Algorithm for Analysis of Variance

Abstract: SUMMARY The general method of analysis of variance described by Wilkinson (1970) is reviewed. The implementation of an algorithm based on this method is described with particular attention to the doubly linked binary tree used to store information about the design. WILKINSON (1970) described a general analysis-of-variance method which enables a single algorithm to analyse most common experimental designs. These designs include all ortho- gonal designs (possibly with several error terms), designs with balanced confounding and other designs with a specified pattern of confounding. The normal equations are not solved directly but by sequentially "sweeping" a working variate which initially contains the data values. The sweep operation calculates effects for a particular term of the linear model from the working variate and uses them to modify it as described below. The algorithm has been implemented as part of the Genstat system (Wilkinson and Rogers, 1974; Nelder et al., 1975). In this paper we review the methods of analysis, explaining how the necessary sequence of sweeps is determined automatically, so that the user only defines the error and treatment terms to be included (together with the treatment combinations applied to each experimental unit). We describe some of the facilities of the program, and how they are implemented, paying

Incorporating checks against observer error into identification keys

Abstract: Summary A method is suggested for checking for errors that may be made when an identification (or diagnostic) key is used. Such errors may arise either from tests being incorrectly used or observed, or because the specimen examined is aberrant or incomplete. The method involves constructing a check key for each endpoint of the main key. Use of the appropriate check key confirms or corrects the initial identification.

Ethirimol-sensitivity in populations of erysiphe-graminis from plots of spring barley

Abstract: SUMMARY Barley plots, cv. Proctor were sown with either ethirimol-treated or untreated seed. At seedling emergence, plots were inoculated with isolates of Erysiphe graminis either sensitive or insensitive to ethirimol, or left uninoculated. Mildew samples taken from the coleoptile leaves of seedlings, and later from leaf 6 (next but one to the flag leaf) were compared for ethirimol sensitivity using probit analysis. Probit lines were derived using ‘Wadley's analysis’. This analysis uses the number of survivors to estimate the total number of individuals originally present. In the test for ethirimol sensitivity a count of colonies on inoculated test leaves was taken to represent survivors. Microscopic counting of the original inoculum was thus avoided. The analyses snowed that the initial leaf inoculation treatments established mildew populations in the plots, which differed considerably in ethirimol sensitivity. Some 6 wk after inoculation the levels of sensitivity in these populations remained unchanged even though inoculum coming into the experiment from external sources was often much more insensitive than the mildew in some plots. Probit lines of response to ethirimol had shallow slopes, showing that large variability exists in the pathogen for this character.