Least Absolute Value vs. Least Squares Estimation and Inference Procedures in Regression Models with Asymmetric Error Distributions

A Monte Carlo simulation is used to compare estimation and inference procedures in least absolute value (LAV) and least squares (LS) regression models with asymmetric error distributions. Mean square errors (MSE) of coefficient estimates are used to assess the relative efficiency of the estimators. Hypothesis tests for coefficients are compared on the basis of empirical level of significance and power

Estimation and Hypothesis Testing in LAV Regression with Autocorrelated Errors: Is Correction for Autocorrelation Helpful?

Using the Prais-Winsten correction and adding a lagged variable provides improved estimates (smaller MSE) in least absolute value (LAV) regression when moderate to high levels of autocorrelation are present. When comparing empirical levels of significance for hypothesis tests, adding a lagged variable outperforms other approaches but has a relative high empirical level of significance

Choosing Smoothing Parameters For Exponential Smoothing: Minimizing Sums Of Squared Versus Sums Of Absolute Errors

When choosing smoothing parameters in exponential smoothing, the choice can be made by either minimizing the sum of squared one-step-ahead forecast errors or minimizing the sum of the absolute onestep- ahead forecast errors. In this article, the resulting forecast accuracy is used to compare these two options

Email: A Note on Hypothesis Tests after Correction for Autocorrelation: Solace for the Cochrane-Orcutt Method?

The behavior of the t test in small samples for coefficient significance in time-series regressions is examined after using the Prais-Winsten (PW) and Cochrane-Orcutt (CO) corrections for autocorrelation. Results are compared to ordinary least squares and generalized least squares

Measurement of Alcohol Use and Misuse in a Cohort of Students Followed from Grade 6 Through Grade 12

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66189/1/j.1530-0277.1994.tb00938.x.pd

Dimensionality, internal consistency and interrater reliability of clinical performance ratings

A total of 6 444 ratings of the financial performance of 4 2 4 third- and fourth-year medical students were made by house officers and attending teachers during 12 separate internal medicine rotations. Ratings were based on 13 behaviourally anchored rating scales. One rating was randomly selected per student per evaluator type (house officer and attending teacher) during each of the 12 rotation periods. Ratings were factor analysed separately within each rotation period. Two factors emerged consistently, and congruence coefficients across the 12 occasions were high (0.88 or greater). The factors were labelled ‘problem-solving (10 items) and ‘interpersonal skills’ (three items) on the basis of their content. Internal consistency coefficients of the indices constructed from items in the two factors and the total of the 13 items were high (0.9 or greater) and did not differ substantially when computed separately on the ratings from house officers and attending teachers. Interrater reliabilities on the individual items ranged from 0.14 to 0.33.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74936/1/j.1365-2923.1987.tb00679.x.pd

An array of strong-motion accelerographs in Bear Valley, California

Fifteen strong-motion accelerographs, each with the capability of writing the WWVB absolute time code on the recorded accelerogram, have been deployed in an elliptical array, at a station spacing of several kilometers, along the San Andreas Fault in the Bear Valley region of central California. Ten accelerograms were obtained for the June 22, 1973, earthquake (M = 3.9), located near the center of the array. Preliminary analyses of these accelerograms support previous suggestions that the crystalline rocks of the Gabilan Range possess higher material velocities and lower intrinsic absorption than do the Cretaceous and Cenozoic sedimentary rocks northeast of the fault zone. These accelerograms clearly indicate that a strong-motion accelerograph array of this sort can provide the basic data for source mechanism, wave propagation, and local ground-motion studies for earthquakes with magnitudes as small as 3.5-4.0

Effectiveness of a High School Alcohol Misuse Prevention Program

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65153/1/j.1530-0277.1996.tb05253.x.pd

Susceptibility to Peer Pressure, Self-Esteem, and Health Locus of Control as Correlates of Adolescent Substance Abuse

As part of a school-based alcohol misuse prevention study, questionnaires were ad ministered to 2,589 fifth and sixth grade students to determine levels of use of alcohol, marijuana, and cigarettes, intentions to use these substances, and problems resulting from alcohol misuse. The questionnaire also included 45 items concerning susceptibil ity to peer pressure, self-esteem, and health locus of control. These 45 items were factor analyzed separately for two groups formed by random assignment. Six factors were identified which were both internally consistent and replicable, and indices were constructed. The indices measuring susceptibility to peer pressure, self-esteem, and internal health locus of control were significantly and negatively correlated with most of the substance use, misuse, and intention items, and an external health locus of con trol index was not significantly related to most of the substance use, misuse, and inten tion items. The "Susceptibility to Peer Pressure" index correlated more highly with the adolescent substance use, misuse, and intention items than the self-esteem or the health locus of control indices, and it had the highest alpha coefficient. Implications for the design of school-based substance abuse prevention programs are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68065/2/10.1177_109019818701400207.pd