摘要:

AbstractIn this paper a new encompassing flexible diffusion model of the epidemic type is proposed and its properties explored. Economic factors are incorporated directly into the model. The new model allows freer interaction between exogenous and endogenous factors in the diffusion process than existing models of this type. The model is applied to the diffusion of colour television ownership in the UK and outperforms the existing models in the literature. The exogenous factors are shown to play a more dominant role in the diffusion of colour television in the UK than existing models allow.

ISSN:0277-6693    

DOI:10.1002/for.3980110702

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractThis paper considers forecasting count data from a multinomial Dirichlet distribution. The forecasting procedure implements hierarchical Bayes methods in order to develop a prior distribution for a new series of data. The methodology is applied to the redemption of cents‐off promotional coupons. In a forecasting experiment, early forecasts of new series are similar to those from pooling all redemptions from previous coupon promotions. However, the hierarchical Bayes model provides realistic estimates of forecasting errors, while those for the pooled forecasts are consistently optimistic. As the current series evolves, the hierarchical Bayes forecasts adapt more rapidly and are more accurate than pooled forecast

ISSN:0277-6693    

DOI:10.1002/for.3980110703

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractThe problem of estimating unknown observational variances in multivariate dynamic linear models is considered. Conjugate procedures are possible for univariate models and also for special very restrictive common components models but they are not generally applicable. However, for clarity of operation and in order to avoid numerical integration, it is desirable to have conjugacy or approximate conjugacy. Such an approximate procedure is proposed based upon a simple analytic approximation. It is exact for the sub‐class of conjugate models and improves on a previous procedure based upon the Robust filte

ISSN:0277-6693    

DOI:10.1002/for.3980110704

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractIn many cases an organization makes predictions of a variable on a yearly scale although the variable is actually observed at shorter time intervals. Given such a yearly prediction, the question will arise as to under which conditions one can say that the actual development of the variable at shorter time intervals deviates so much from the year estimate as to render the latter implausible. Policy makers confronted with such a problem tend to use rather primitive statistical methods of inference. In this paper the situation is judged from a statistical point of view and placed in the context of the ‘significance test’ approach to control chart theory. It is assumed that the variables are generated by a multivariate autoregressive moving average model. Thus we derive an approximate distribution of the future observations of the series given the values of some linear compounds of the variables. With this, three control charts can be constructed. The approach is illustrated by an example based on the monthly tax returns of the Dutch central government. The example suggests the usefulness of the approach in many practical situations of forecasting and plann

ISSN:0277-6693    

DOI:10.1002/for.3980110705

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

ISSN:0277-6693    

DOI:10.1002/for.3980110701

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY