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831.
832.
A contingency table of the mc form provides a convenient summary of data when c individuals in a matched set9 each belonging to a different one of c classifications, are identified as belonging to one of m categories, A study in which matched sets (c=3) of 1 case, 1 hospital control, and 1 neighborhood control are classified into one of m=4 occupational categories would be an example, Independence in the cxm tables for each of the matched sets implies symmetry in the summary mc table with consequent marginal homogeneity. Adaptation of the Mantel-Haenszel procedure for testing independence to the case of many cxm tables so as to yield a chi square with (cl)(ml) degrees of freedom (DF) provides a test of marginal homogeneity in the summary mc table. This can be viewed as a test of symmetry directed against alternatives which would make for marginal inhomogeneity and can differ 相似文献
833.
In this article, we propose a general method for testing the Granger noncausality hypothesis in stationary nonlinear models of unknown functional form. These tests are based on a Taylor expansion of the nonlinear model around a given point in the sample space. We study the performance of our tests by a Monte Carlo experiment and compare these to the most widely used linear test. Our tests appear to be well-sized and have reasonably good power properties. 相似文献
834.
T. P. Hutchinson 《Mathematical Population Studies》2013,20(3-4):209-216
Methods are given for estimating the average years of life lost when a person is discovered to be at risk from an extra hazard. The methods use the probability per year of the extra risk striking, and the mean and standard deviation of lifetime in the absence of the risk. The formulae are simple enough that only a hand‐held calculator is needed. 相似文献
835.
This paper proposes a functional connectivity approach, inspired by brain imaging literature, to model cross-sectional dependence.
Using a varying parameter framework, the model allows correlation patterns to arise from complex economic or social relations
rather than being simply functions of economic or geographic distances between locations. It nests the conventional spatial
and factor model approaches as special cases. A Bayesian Markov Chain Monte Carlo method implements this approach. A small
scale Monte Carlo study is conducted to evaluate the performance of this approach in finite samples, which outperforms both
a spatial model and a factor model. We apply the functional connectivity approach to estimate a hedonic housing price model
for Paris using housing transactions over the period 1990–2003. It allows us to get more information about complex spatial
connections and appears more suitable to capture the cross-sectional dependence than the conventional methods. 相似文献
836.
We describe a first experiment on whether product complexity affects competition and consumers in retail markets. We are unable
to detect a significant effect of product complexity on prices, except insofar as the demand elasticity for complex products
is higher. However, there is qualified evidence that complex products have the potential to induce consumers to buy more than
they would otherwise. In this sense, consumer exploitability in quantities cannot be ruled out. We also find evidence for
shaping effects: consumers’ preferences are shaped by past experience with prices, and firms may in principle exploit this
to sell more. 相似文献
837.
A Diamond-Stiglitz approach to the demand for self-protection 总被引:1,自引:0,他引:1
The existing research concerning the relationship between risk aversion and prudence and the demand for self-protection assumes
that the loss variable follows a Bernoulli distribution, and that changes in the level of self-protection are mean preserving.
The analysis here replaces these two very strong conditions with ones which are more general. When doing this, the method
of analysis is also significantly modified. This modification includes representing a change in the level of self-protection
using the procedure developed by Diamond and Stiglitz (Journal of Economic Theory 8:337-360, 1974) for representing a change in risk. This alternate representation allows the existing findings to be generalized considerably,
and also simplifies the analysis. 相似文献
838.
Sheretta T. Butler-Barnes Stephanie Cook Seanna Leath Cleopatra Caldwell 《Race and social problems》2018,10(1):30-41
This study explored the extent to which private regard and religiosity beliefs serve as protective factors for school bonding among African American and Caribbean black adolescents who experience racial discrimination in school. Findings are drawn from a nationally representative sample of (n = 810) African American and (n = 360) Caribbean black adolescents (52% girls) aged 13–17 (Mage = 15, SD = 1.42) years. Results suggest that perceiving racial discrimination from teachers was associated with lower levels of school bonding for African American and Caribbean black adolescents. For African American adolescents, perceiving more racial discrimination from teachers and reporting lower private regard beliefs was associated with less school bonding. The findings for Caribbean black adolescents revealed that endorsing moderate levels of religiosity and perceiving higher rates of teacher discrimination was associated with less school bonding. The developmental significance and implications for future research are discussed. 相似文献
839.
Ralph S. J. Koijen Motohiro Yogo 《Econometrica : journal of the Econometric Society》2016,84(3):1265-1287
Life insurers use reinsurance to move liabilities from regulated and rated companies that sell policies to shadow reinsurers, which are less regulated and unrated off‐balance‐sheet entities within the same insurance group. U.S. life insurance and annuity liabilities ceded to shadow reinsurers grew from $11 billion in 2002 to $364 billion in 2012. Life insurers using shadow insurance, which capture half of the market share, ceded 25 cents of every dollar insured to shadow reinsurers in 2012, up from 2 cents in 2002. By relaxing capital requirements, shadow insurance could reduce the marginal cost of issuing policies and thereby improve retail market efficiency. However, shadow insurance could also reduce risk‐based capital and increase expected loss for the industry. We model and quantify these effects based on publicly available data and plausible assumptions. 相似文献
840.