In order to determine whether an existing tree volume estimation equation is acceptable for application to a new species, a new region or a local area, an accuracy test could be carried out. Three sequential accuracy testing plans (SATP) were developed, along with approximate separating Characteristic and Average Sample Number curves. These tests are extensions of Freese's (1960) fixed sample size accuracy tests using Wald's (1947) sequential probability ratio tests (SPRT). Using Monte Carlo simulations with normally distributed error terms, the SATP procedures were shown to be reliable for classifying existing volume models as acceptable or not acceptable with achieved error probabilities (Type I and Type II error probabilities) that were very close to those specified prior to testing. Also, on average, the use of the SATP procedures will result in a 40 to 60 % reduction in sample size compared to an equally reliable conventional fixed sample size procedure. A detailed example is given to illustrate the application of the SATP procedures. Some results from comparing the performance of this parametric sequential procedure to previously developed nonparametric sequential procedure will also be presented.
Keywords: statistic, testing.
Correspondence: Valerie M. LeMay, Dep. of Forest Resources Management, Faculty of Forestry, University of British Columbia, 270-2357 Main Hall, Vancouver, B.C. V6T 124, Canada
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