A wide range of tests for heteroskedasticity have been proposed in the econometric and statistics literature. Although a few exact homoskedasticity tests are available, the commonly employed procedures are quite generally based on asymptotic approximations which may not provide good size control...

Economists have long advised pricing electricity at marginal cost. In the case of public utilities producing from hydraulic sources, this would ordinarily generate a rent that could be used to finance public projects or to lower taxes. But marginal cost pricing by public utilities is rarely...