EVENT: Soil&Water Seminar, May9:

An Soil&Water seminar on Weds, May 9th at 12pm will be given by Prof. Richard Webster. All welcome!

TITLE: "Presentation of statistics in scientific papers " R Webster, Rothamsted Research

ABSTRACT: This talk is about what information to present in papers on soil research in which the most used statistical techniques have had crucial roles. In all instances state what you did, important intermediate results and what you found.

1. For surveys summarize the sampling scheme and the data, transformed if necessary, that accrued. 2. For designed experiments describe the design, analyse the variance according the design, summarize the analysis in a table and list means and their standard errors. 3. Distinguish correlation from regression. Regression is about prediction mainly. State which variable is the predictor and which is the predictand. Give the equation and display it on a scatter graph. 4. For principal component analysis state on which matrix you did the analysis, list the eigenvalues and graph the eigenvectors or correlations derived from them. 5. In geostatistical studies summarize the data, display a posting of them, show the variogram and state how you computed and modelled it, and list its parameters.

I shall illustrate these items with data and results from case studies.

ABOUT THE SPEAKER: Richard Webster, after graduating in chemistry at Sheffield University, worked as soil chemist for the Government of Northern Rhodesia (now Zambia). He returned to England, to Oxford University, to investigate methods for predicting soil conditions at remote sites for which he was awarded his doctorate. He continued that research at Rothamsted Experimental Station and for one year (1973) with CSIRO in Canberra. In 1990 he was appointed charge de recherche in the Paris School of Mines from where he moved to the Institut de la Recherche Agronomique in Montpellier. He was guest professor at the Swiss Federal Institute of Technology in Zurich and Lausanne before returning once more to Rothamsted to edit the European Journal of Soil Science. Richard Webster is currently a Lawes Trust Senior Fellow at Rothamsted, visiting professor in the Universidad Nacional Autonoma de Mexico and visiting scientist with CSIRO.