4.Journals Published in Sri Lanka
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Item Use of covariates in improving precision of field experiments in rubber(Postgraduate Institute of Agriculture, University of Peradeniya:Peradeniya, 1996) Wijesuriya, B.W.; Thattil, R.O.Item Control of variability in experiments with rubber using covariance technique. a review(Rubber Research Institute. Agalawatta, 1997) Wijesuriya, B.W.; Thattil, R.O.Comparatively little has been published on experimental techniques and statistical methods in rubber.This paper is a review of available literature on the use of covariates in experiments falling into immature and mature stages of rubber.The main objective is to encourage researchers to collect appropriate pre-treatment records to adjust the post.treatment variables so as to obtain high precision of results.In this connection,the effectiveness of rubber yield,girth and panel variables as pre-treatment records during the mature stages;seed and budded stump weights as covariates during the immature stages are discussed.The use of double covariance and other possible approaches to minimize initial variability in fertilizer,pest and disease,weed and green house experiments are also discussed.Item Analysis of ranking exercises in participatory rural appraisal (PRA). a case study from the smallholder rubber sector(Rubber Research Institute. Agalawatta, 2005) Wijesuriya, W.; Thattil, R.O.Item Methods of data analysis for intercropping systems under rubber(Rubber Research Institute. Agalawatta, 2001) Wijesuriya, W.; Thattil, R.O.Item Evaluation of ISO recommendation on analysis of precision experiments for statistical quality control(Rubber Research Institute. Agalawatta, 1999) Wijesuriya, W.; Thattil, R.O.Application of appropriate statistical methods is an important task in any quality control process as various statistical approaches such as;sampling,experimentationand process control are involved in quality control lprocesses.This has become an essential practice in many areas since the introduction of ISO quality assurance scheme .This article focuses on precision experiments where several laboratories are compared for a standard measurement method.The whole plrocess of analysis and interpretation suggested by ISO is evauated and documented in a sequential order.In addition to the ISO recommendation,additional graphical methods are suggested for better judgement .The statisticans role as a member of the panel is also lpresented at each step of the quality control process.