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61.
62.
63.
In this paper, the task of determining expected values of sample moments, where the sample members have been selected based on noisy information, is considered. This task is a recurring problem in the theory of evolution strategies. Exact expressions for expected values of sums of products of concomitants of selected order statistics are derived. Then, using Edgeworth and Cornish-Fisher approximations, explicit results that depend on coefficients that can be determined numerically are obtained. While the results are exact only for normal populations, it is shown experimentally that including skewness and kurtosis in the calculations can yield greatly improved results for other distributions. 相似文献
64.
Y. K. Ng 《Social Choice and Welfare》1989,6(2):87-101
Individual preferences inconsistent with personal welfare caused neither by ignorance nor by a positive consideration for the welfare of others are defined as (welfare) irrational. Sources of irrationality (rigid adherence to moral principles, excessive fear of danger, excessive tempetation of pleasure, revenge, inertia, faulty telescopic faculty, the fallacy of diminishing marginal utility of utility, etc.) are discussed. An evolutionary explanation of irrationality is suggested and some implications for individual decision and social policy indicated.I am grateful to two anonymous referees for comments. 相似文献
65.
Oheneba-sakyi Y 《Sociological perspectives : SP : official publication of the Pacific Sociological Association》1989,32(4):485-500
A comparison of cohorts of ever-married Chanaian women suggests evidence of a fertility transition beginning among younger women and select subgroups. Ghana's crude birth rate declined from a high of 50/1000 population in 1970 to 38.8/1000 in 1985. To ascertain whether marital fertility is now being controlled through conscious attempts to lengthen birth intervals, World Fertility Survey data from 1979-80 on the timing of births among different birth cohorts were analyzed. It was hypothesized that, as a result of the influence of Western values that stress independence from parents and the introduction of compulsory education, cohorts of the mid-1950s and 1960s would be more likely to postpone childbearing, more active in the modern sector of the economy, and more accepting of modern contraceptive usage for birth spacing than women in the 1930-39, 1940-49, and 1950-59 cohorts. For the 1940-49 cohort, it took 10.8 months for 25% to have a birth following 1st marriage, 18.7 months for 50% to have a 1st birth, and 27.4 months for 75% to complete this step. By comparison, these figures for the 1955-64 birth cohort were 9.9, 16.7, and 20.5 months, respectively. The significantly shorter (p 0.01) interval between marriage and 1st birth found among younger women in part reflects rising age at marriage; mean age at 1st marriage was 17.9 years for the 1940 cohort and 21.6 years for the most recent cohort. After the birth of the 1st child, recent cohorts were more likely to wait longer for the 2nd birth. For women born in 1950-64, it took 21.8, 36.7, and 44.6 months for 25%, 50%, and 75%, respectively, to reach parity 2. This pattern of lengthened birth interval beyond the 1st birth was apparent at all parities in the youngest cohort and indicates increasing acceptance of contraception among those who have come of age during a period of rapid social change. 相似文献
66.
Hu Y 《International journal of sociology of the family》1988,18(1):57-78
The relationship between family support systems and female mortality in Chinese and American cultures is studied using 1980 official data from Taiwan and the United States. The differences in female mortality by marital status support the hypotheses that Chinese families provide greater support for older than younger females, and that the emphasis on filial piety in Chinese society provides more support for the elderly by Chinese than American children. 相似文献
67.
This study proposes and demonstrates an analytic paradigm based upon a substantive categorization of a set of inmigration correlates. It exemplifies the notion of categorizing, analyzing according to the categorization, and subsequently discussing the phenomenon in more depth. The paradigm has 2 steps: 1) the variables are categorized according to the cells resulting from the intersection of a preferably small number of nominal dimensions and 2) the data are analyzed, directly anchored in the prior categorization. The data used is Israel's 1983 census macro-data gathered from the Central Bureau of Statistics for the Israeli towns with populations of at least 5000. The authors defined 6 variables as push variables and 4 as pull variables. Results of the regression employing push variables show that 4 variables accounting for 72% of inmigration were found to significantly predict inmigration: 1) unemployment, 2) percentage of Asians-Africans, 3) town size, and 4) religiosity. Within the pull classification, the regression analysis reveals that 2 of the 4 variables explain 31% of the inmigration variance: 1) educational level (26%) and 2) income (5%). The 1st regression analysis on the 2nd dimension shows that the percentage of Asian-African origin and town population size account for 32% of the immigration variance. In the 2nd regression analysis, unemployment explains 48% of the inmigration variance and educational level explains 8%. In the 3rd regression, only home crowding explains a significant amount of the immigration variance (19%). Results of a multiple regression analysis show that unemployment level, percentage of Asian-Africans, population size, and level of religiosity account for 72% of the inmigration variance. Thus, the characteristics of a town inmigrating (push variables) are demographic, economic, and social. However, the attractive features of a town are only economic. Among all economic factors, unemployment is primary. In addition, not only are both percentage of Asians-Africans and population size significantly deflective of inmigration, but each also plays a separate and independent role. 相似文献
68.
Litvin Y 《Vestnik statistiki (Moscow, Russia : 1949)》1988,(3):50-56
Methods that have been used or suggested to improve the accuracy of the U.S. census are reviewed. The author notes that self-completed questionnaires yield better results than those completed by census enumerators. The use of sample surveys carried out as part of the census process is described. 相似文献
69.
A comparative study conducted in the Sudan illustrated both the potential of a nutrition education program for pregnant women and the many obstacles to creating more optimal maternal nutrition. Included in the study were 1200 women 18-34 years of age attending the Khartoum Province Model Clinic for a minimum of 5 prenatal visits. 83.3% were Muslims and 48.2% were illiterate. The 60 women who comprised the experimental group were exposed to individual nutrition counseling and home visits. Overall, 70% of subjects were anemic, 27% had malaria, and 18% were hookworm. The average weight gain during pregnancy was 4.5 kgs; 25.0% of controls and 20.0% of those in the experimental group gained 3.5-4.0 kgs, 18.3% of controls and 33.3% of experimental subjects gained 4.5-5.0 kgs, and 23.3% of controls and 30.0% of those in the experimental groups gained 5.5 kgs or more. 53.0% of controls and 61.7% of women exposed to nutrition education breastfed for at least 6 months, and 70% of women in the former group and 95% of those in the latter had enrolled their infants in an immunization program. A baseline nutrition questionnaire revealed widespread misinformation, especially a belief that pregnant women should reduce their food intake from 3 to 1-2 meals per day to prevent the fetus from growing too large and making labor difficult. Foods such as fermented sorghum products, fresh fish, and water melon were regarded as abortifacients and avoided, while hot pepper, sour milk, and cola sodas were considered nutritious. Consumption was self-reported to be poor for milk products by 25% of mothers, for meat by 16%, and for fruits and vegetables by 40% Although the educational intervention increased women's knowledge of basic nutrition, it had only a minimal effect on actual practice. This finding is assumed to reflect the widespread belief that men and their guests should be given preference in food allocation, poverty, and avoidance, on the basis of tradition, of many healthy foods. Since 72% of women reported ownership of a television, use if this medium is recommended for nutrition education. 相似文献
70.
"This article revises the Coale-Trussell method for analyzing data from the World Fertility Survey by proposing and testing alternative log-linear and log-multiplicative models. The models, in one form or another, represent the structural constraint underlying the Coale-Trussell method on the variation in the age pattern of human fertility. With a Poisson distribution assumption for the number of births, several parameters of the models are simultaneously estimated via maximum likelihood. It is shown that the new approach can be adopted whenever fertility limitation is compared across multiple populations or subpopulations." 相似文献