Improved Regression Estimation of a Multivariate Relationship with Population Data on the Bivariate Relationship

Regression coefficients specify the partial effect of a regressor on the dependent variable. Sometimes the bivariate or limited multivariate relationship of that regressor variable with the dependent variable is known from population-level data. We show here that such population- level data can be used to reduce variance and bias about estimates of those regression coefficients from sample survey data. The method of constrained MLE is used to achieve these improvements. Its statistical properties are first described. The method constrains the weighted sum of all the covariate-specific associations (partial effects) of the regressors on the dependent variable to equal the overall association of one or more regressors, where the latter is known exactly from the population data. We refer to those regressors whose bivariate or limited multivariate relationships with the dependent variable are constrained by population data as being ‘‘directly constrained.’’ Our study investigates the improvements in the estimation of directly constrained variables as well as the improvements in the estimation of other regressor variables that may be correlated with the directly constrained variables, and thus ‘‘indirectly constrained’’ by the population data. The example application is to the marital fertility of black versus white women. The difference between white and black women’s rates of marital fertility, available from population-level data, gives the overall association of race with fertility. We show that the constrained MLE technique both provides a far more powerful statistical test of the partial effect of being black and purges the test of a bias that would otherwise distort the estimated magnitude of this effect. We find only trivial reductions, however, in the standard errors of the parameters for indirectly constrained regressors.

CONTROLLING YELLOW-BILLED MAGPIES (Pica nuttalli)

The yellow-billed magpie is a little smaller than the American or black-billed magpie, but the difference in size is very slight. The birds look exactly alike, except one has a black beak and the other has a yellow bill and a bit of yellow skin back of the eye.There are concentrated populations in the Los Banos area, Gustine area, and along the course of the Merced River comprising about 19,100 acres. They are occasionally seen in other areas of the County, but only infrequently observed in the southwestern portion of the County. The heaviest populations are in walnut orchards, dairy farms, almond orchards, turkey ranches and areas adjacent to river bottoms.The yellow-billed magpie may represent a dying ancient race. Since scientific interest has been directed toward its habits and distribution, its range has become more restricted. There are reports that 50 or 60 years ago it was common in many places close to the Coast, where the observer would now look for it in vain. It inhabits only the interior of California west of the Sierra Nevada, chiefly in the Sacramento and San Joaquin Valleys. It haunts stock ranches, because food to its liking is usually plentiful in such places. When cattle and sheep are butchered the refuse attracts magpies. They gather about any dead animal. They feed on grasshoppers, worms and grubs, and of course always look for a reasonable supply of eggs.

African American and Teaching in Higher Education IS a Course on Race and Culture

Using theoretical applications, the authors present an overview of theories that highlight approaches for teaching culturally sensitive content, personal experiences as educator and colleague in a predominantly white college campus and strategies for addressing culturally insensitive experiences in and outside the classroom. Presenters focus on the recruitment and retention of people of color and stress the need for today's predominantly white institutions to become more knowledgeable, tolerant and sensitive about their environments in an effort to make them more accepting.