On UMV-EStimators in survey sampling

Summary The existence of uniformly minimal variance estimators in the class of all linear unbiased estimators of the population total is discussed. Some remarks are given on the concept of necessary bestness.

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Zusammenfassung Es wird die Existenz von Schätzungen mit gleichmäßig minimaler Varianz in der Klasse aller linearen erwartungstreuen Schätzungen des Populationstotales besprochen. Einige Bemerkungen werden zum Begriffi necessary bestness gemacht.

     

Levensduur en sloop van personenauto's in Nederland, 1950–1964*

Summary The life distribution of motorcars is examined over the period from 1950 to 1964. Age-specific survival rates, derived from Dutch registrations, are averaged and lead to the life table shown in table 4. The deviations from average age-specific survival rates show no significant variation over time nor over successive car generations. Since the registrations include an increasing number of used cars imported from Germany this apparent stability hides compensating changes in car scrap page. Since before the war the life expectancy of motorcars has increased from 8 to 11 years, and it is argued that this is due to the widening of the used car market. In the next stage, which is already well under way in Germany, new cars replace used cars, and rising apparent scrappage rates reflect the disposal of the latter by export.     

The effects of group decision-making process and problem-situation complexity on implementation attempts

The effects of group problem-solving method and problem-situation complexity on attempts at implementing group solutions were investigated in a laboratory-field setting. Group members were supervisory nurses from various organizations, who were randomly assigned to three groups in a balanced research design which included three group decision-making processes and three levels of problem-situation complexity in implementation. The dependent variable was the number of attempts at implementing group-derived solutions in home organizations. The results showed that structure in group decision-making processes led to increased rates of implementation attempts at all levels of problem-situation complexity. There was a significant complexity-by-process interaction effect among the decision-making processes, which supports the conclusion that the type of group decision-making process and the problem-situation complexity should be considered in order to optimize the number of implementation attempts.g     

A child health production function estimated from longitudinal data. Cebu Study Team

Collaborating researchers used a multi equation model to analyze 3080 mother-infant pairs living on the island of Cebu in the central Philippines and to estimate a child health production function. The econometric methods used eliminated obstacles such as heterogeneity and endogeneity of significant explanatory factors. They also maximized the longitudinal quality of the data. The results showed that morbidity in 1 period reduced infant weight in following periods. For example, diarrhea and febrile respiratory infection reduced growth in the time period following the illnesses. Further effects of some contributing factors were great near birth not diminished with age. For example, breast feeding promoted growth and protected against infection, especially diarrhea and febrile respiratory infection, more substantially near birth than it did later. Further, in urban areas, preventive health care positively affected growth independently of its indirect influence on reducing respiratory infection. Yet it had little effect on diarrhea. Diarrhea had a strong adverse effect on growth. Exposure of the infant to enteric pathogens had the greatest influence on production of diarrhea. In urban areas, exposure included water supply contamination, exposure to feces, a more pathogenic diet, and community crowding. In rural areas, however, exposure included community crowding and increased rainfall which presumably washed feces into the water supply. Household crowding in both urban and rural areas and irritation from smoke in urban areas only tended to bring about febrile respiratory infection.