Small Programmable Calculators For Computing Statistical Tests

Volume 2 of Insecticide and Acaricide Tests contains ]96 reports on field evaluation of chemicals for controlling insects and mites. All these field experiments were important and involved a great deal of effort and expense. However, 36% of the reports have no statistical confidence limits or results and interpretation of statistical tests. Statistical treatment of research data is extremely useful, if not necessary, in interpreting results and drawing valid conclusions from field experiments. The reasons for replicating field experiments in a proper design are twofold: (1) to have greater confidence in the results obtained and (2) to measure the inherent variability in the experiment and, by application of appropriate statistical tests, to determine differences among treatments that are due to treatment effects and not to natural variability. These and other considerations on the design of field experiments, selection of proper statistical tests, and interpretation of results are discussed in an article by Dr. Larry A. Nelson in Volume I, Insecticide and Acaricide Tests. Probably the principal reasons for the lack of statistical analysis in many reports is the time consuming and complex nature of the computations required and the problems associated with arithmetic errors. These problems have been somewhat alleviated in recent years by increasing availability of computing centers and consulting statisticians at most universities and in private industry. These services are indispensable for processing data from large, complex tests. However, computing services are not without drawbacks, especially for the less complex smaller field experiments. These drawbacks include data which must be submitted in special format, charges for the service, instructions which may be misunderstood, and “turn around time” which often exceeds a week or even a month. For some entomologists, computing services may be virtually unavailable.