The increased interest in the variability of soil properties is responsible for recent observations that soil variables are not normally distributed but are more closely approximated by the two-parameter lognormal frequency distribution. Statistical methods commonly applied in the estimation of...

The authors build a model of child labor and study its implication for welfare and fertility. Assuming there is a trade-off between child labor and human capital accumulation, we derive conditions under which child labor is socially inefficient. Even if parents are altruistic, child labor may...

The autors study the implications of the trade-off between child quality and child quantity for the efficiency of the rate of population growth. They show that if quantity and quality are inversely related then, even in the case of full altruism within the family, population growth is...

Plant breeders traditionally have estimated genotypic and phenotypic correlations between traits using the method of moments on the basis of a multivariate analysis of variance (MANOVA). Drawbacks of using the method of moments to estimate variance and covariance components include the...

Although the U.S. Congress established the Total Maximum Daily Load (TMDL) program in the original Clean Water Act of 1972, Section 303(d), it did not receive attention until the 1990s. Currently, two methods are available for tracking pollution in the environment and assessing the effectiveness...