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31.
Although picture‐book reading is commonplace during infancy, little is known about the impact of this activity on learning. A previous study showed that 18‐ and 24‐month‐olds imitated a novel action sequence presented in a book that was illustrated with realistic color photos, whereas they failed to imitate from books illustrated with less realistic drawings. In the research reported here, we hypothesized that increasing infants' exposure to a picture book would increase learning from books illustrated with both color photos and drawings. Independent groups of 18‐and 24‐month‐olds were exposed to a picture book either twice in succession or 4 times in succession. The results showed that, regardless of the iconicity of the illustrations, increasing the number of reading sessions significantly improved the infants' imitation scores, compared to age‐matched, no‐demonstration controls. The results are discussed in relation to representational insight and cognitive flexibility. 相似文献
32.
Bram Thuysbaert 《Journal of Economic Inequality》2008,6(1):33-55
Empirical applications of poverty measurement often have to deal with a stochastic weighting variable such as household size.
Within the framework of a bivariate distribution function defined over income and weight, I derive the limiting distributions
of the decomposable poverty measures and of the ordinates of stochastic dominance curves. The poverty line is allowed to depend
on the income distribution. It is shown how the results can be used to test hypotheses concerning changes in poverty. The
inference procedures are briefly illustrated using Belgian data.
An erratum to this article can be found at 相似文献
33.
Singh et al. ([13]) pointed out that the Randomized response (RR) technique proposed by Moors ([9]) is not desirable because
it fails to protect the confidentiality of the respondents and they provided two alternative strategies free from the above
drawback but limited to SRSWOR sampling only. In this paper, generalization of one of the strategies is provided for complex
survey designs, wider class of estimators and for quantitative characteristics. Relative efficiency of the modified strategy
is tested through empirical investigations.
An erratum to this article is available at . 相似文献
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We define a class of count distributions which includes the Poisson as well as many alternative count models. Then the empirical probability generating function is utilized to construct a test for the Poisson distribution, which is consistent against this class of alternatives. The limit distribution of the test statistic is derived in case of a general underlying distribution, and efficiency considerations are addressed. A simulation study indicates that the new test is comparable in performance to more complicated omnibus tests. 相似文献
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39.
Previous studies have shown that 7.5‐month‐olds can track and encode words in fluent speech, but they fail to equate instances of a word that contrast in talker gender, vocal affect, and fundamental frequency. By 10.5 months, they succeed at generalizing across such variability, marking a clear transition period during which infants' word recognition skills become qualitatively more mature. Here we explore the role of word familiarity in this critical transition and, in particular, whether words that occur frequently in a child's listening environment (i.e., “Mommy” and “Daddy”) are more easily recognized when they differ in surface characteristics than those that infants have not previously encountered (termed nonwords). Results demonstrate that words are segmented from continuous speech in a more linguistically mature fashion than nonwords at 7.5 months, but at 10.5 months, both words and nonwords are segmented in a relatively mature fashion. These findings suggest that early word recognition is facilitated in cases where infants have had significant exposure to items, but at later stages, infants are able to segment items regardless of their presumed familiarity. 相似文献
40.
Gabriela Beganu 《Statistical Methods and Applications》2007,16(3):347-356
It is known that the Henderson Method III (Biometrics 9:226–252, 1953) is of special interest for the mixed linear models
because the estimators of the variance components are unaffected by the parameters of the fixed factor (or factors). This
article deals with generalizations and minor extensions of the results obtained for the univariate linear models. A MANOVA
mixed model is presented in a convenient form and the covariance components estimators are given on finite dimensional linear
spaces. The results use both the usual parametric representations and the coordinate-free approach of Kruskal (Ann Math Statist
39:70–75, 1968) and Eaton (Ann Math Statist 41:528–538, 1970). The normal equations are generalized and it is given a necessary
and sufficient condition for the existence of quadratic unbiased estimators for covariance components in the considered model. 相似文献