This paper describes a method for testing a parametric model of the mean of a random variable <italic>Y</italic> conditional on a vector of explanatory variables <italic>X</italic> against a semiparametric alternative. The test is motivated by a conditional moment test against a parametric alternative and amounts to replacing...

Positive definiteness of income effect matrices provides a sufficient condition for the <italic>law of demand</italic> to hold. Given cross section household expenditure data, empirical evidence for the law of demand can be obtained by estimating such matrices. Härdle, Hildenbrand, and Jerison used the...