12 research outputs found


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    We investigate three alternative models for estimating the mean of a population using double sampling survey techniques. One estimator was found in the range science literature (Cook and Stubbendieck, 1986), another is the estimator presented by Cochran (1977). The third estimator uses method-of-moments estimators with measurement error regression models. Simulation studies suggest that the measurement error model does not work well when the slope is appreciably different from unity. Delta method variance estimators of the measurement error model may give negative variance estimates under these circumstances. The other estimators have better small sample performance (both are approximately unbiased, and have similar variances), but the two estimators have very different estimated variances under some circumstances

    ESTIMATING MIXTURE FRACTION AND MAP DISTANCE IN A MIXED F\u3csub\u3e2\u3c/sub\u3e, BC\u3csub\u3e1\u3c/sub\u3e POPULATION

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    An F1 interspecific hybrid onion (Allium cepa x A. fistulosum) was backcrossed to the A. cepa parent line under field conditions. The progeny of this cross were shown by electrophoretic protein analysis to be a mixture of BC1 (the desired backcross) and F2 (A. cepa x A. fistulosum) x (A. cepa x A. fistulosum) individuals. This mixture of populations among the progeny render the usual X2 test for independent segregation of loci invalid. F2 is used to denote progeny derived from either selfing of the F1 or from sib-crosses between two F1 individuals. A model for this mixed population has been developed; from this model the mixture fraction and crossover frequencies can be estimated using maximum likelihood

    Some statistical aspects of the calibration problem

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    Typescript (photocopy).Digitized by Kansas Correctional Industrie

    A Cohort Approach for Predicting Future Eating Habits: The Case of At-Home Consumption of Fresh Fish and Meat in an Aging Japanese Society

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    Due to a rapidly aging society, stagnating per capita income and rather stable prices, traditional economic analyses methods lost their power in the 1990s to predict future food product consumption in Japan. This study, in part, remedies this problem by projecting future consumption of selected products, using a cohort approach with economic factors tentatively set aside. Per capita consumption of individual household members by age was derived by incorporating family age composition into household data classified by age groups of household head (HH). Individual consumption estimates were decomposed into age, cohort and time effects, using the Nakamura's Bayesian cohort model. These effects were synthesized to predict per capita consumption in each population age cell in 2010 and 2020. Although some method refinement is warranted, the cohort approach proves a useful tool in improving prediction of future food product consumption and, combined with economic factors, may prove useful in future economic forecasting

    How often is prep close to the true replication probability?

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    Declining Orange Consumption in Japan: Generational Changes or Something Else?

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    Japan is a leading market for U.S. oranges. Since 1995, orange consumption in Japan has declined. This report summarizes an analysis of household survey data to assess various factors that may be related to the decline. Consumption of oranges in Japan differs markedly across generations, with younger generations (cohorts) eating fewer oranges than older generations. However, within generations, as individuals in Japan grow older, they eat more oranges. On balance, the effects on consumption associated with aging and birth cohort membership are mostly offsetting. Orange prices affect consumption levels, but household income does not. Even after the analysis accounts for price and demographic variables, a strong downward trend is evident in orange consumption in Japan. Results suggest that orange consumption could decline even more in the future