In this paper, we analyze the properties of nonparametric estimators of a regression function when some covariates are not directly observed, but have only been estimated by some nonparametric procedure. We provide general results that can be used to establish rates of consistency or asymptotic normality in numerous econometric applications, including nonparametric estimation of simultaneous eq...

Quantitative structure–activity relationships (QSARs) and quantitative structure–property relationships (QSPRs) rely on regression equations containing numerical descriptors of molecular structure. In constructing these models, highly correlated descriptors are sometimes excluded from the regression equations. Although this exclusion seems reasonable, in fact it can lead investigators to overlo...

BACKGROUND AND OBJECTIVES Height is an essential measurement in clinical medicine. It allows the calculation of body mass index, ideal body weight, basic energy requirements and tidal volumes. In many patient groups, such as the critically ill, height cannot be measured easily and surrogate anthropometric measures are used. Regression equations estimating height are specific to ethnicity. We ai...

The correlation between body mass and both skeletal and dental measures in living mammals has enabled paleontologists to obtain reliable estimates of body size for extinct species, usually using log-transformed bivariate least-squares regression equations. Multiple regression, however, has rarely been used for estimating the mass of extinct species, although this technique can clearly improve t...

BACKGROUND Plasma osmometry and the osmol gap have long been used to provide clinicians with important diagnostic and prognostic patient information. OBJECTIVE We compared different equations used for predicting plasma osmolality when its direct measurement was not practical or an osmol gap was of interest and identified the best performers. DESIGN The osmolality of plasma was measured by u...

BACKGROUND Differences in minute ventilation between cyclists, pedestrians and other commuters influence inhaled doses of air pollution. This study estimates minute ventilation of cyclists, car and bus passengers, as part of a study on health effects of commuters' exposure to air pollutants. METHODS Thirty-four participants performed a submaximal test on a bicycle ergometer, during which hear...

There is good correlation between the specific gravity and osmolality of urine obtained from neonates and adults, if specimens contain neither protein nor glucose. The regression equations between specific gravity and osmolality, however, differ considerably between the two age groups, maturation to the adult regression occurring within the first 5 years of life. Specifically derived regression...

Prediction of maximum local scour is necessary for the safety and economical design of the bridges. A number of equations have been developed over the years to predict local scour depth using laboratory data and a few pier equations have also been proposed using field data. Most of these equations are empirical in nature as indicated by the past publications. In this paper attempts have been ma...