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The article presents comments of Paul T. David on the paper related to competition in air transport written by Kent T. Healy. According to David, the first half of Healy's paper is an analysis in terms of input-output factors, while the second is concerned mainly with geographic patterns, homogeneity of markets geographically, and the question of the optimum number of competing carriers in a single market. This order of analysis might possibly have been reversed with some advantage, since the input-output factors acquire competitive importance mainly within the framework of geographic relationships. Commenting on professor Healy's paper, he says that he found it most stimulating. He was particularly glad to see the emphasis upon the need for a sufficient number of air transport enterprises to provide full scope for innovation and fresh talent. The tendency abroad has been in the opposite direction. For this and other reasons, the problem of establishing workable conditions of competition on the international air routes is full of special complexities and will continue to present major difficulties.

In this paper the authors hypothesize that hierarchically differentiated groups will (1) exhibit less risk-taking behavior, (2) be less efficient, and (3) be less productive than hierarchically undifferentiated groups. To test the hypotheses, 10 hierarchically differentiated groups and 10 hierarchically undifferentiated groups formed from the staffs of 10 elementary schools were given a problem, in logic. Results confirmed all three hypotheses at the analysis phase of problem-solving. Too few groups solved the problem to permit testing of the third hypothesis at the synthesis phase of problem solving. [ABSTRACT FROM AUTHOR]

The results of this paper are summarized in table 1 which describes the restrictions on the profit functions under alternative assumptions on the technology. The alternatives considered are as follows: (1) Almost homogeneity of the transformation function (2) Direct separability (3) Indirect separability (4) Non-jointness in inputs (5) Non-jointness in outputs [ABSTRACT FROM AUTHOR]

Three samples of priests in the Archdiocese of Seattle were polled concerning their views on paramount values. Three questionnaire versions were used and about 40 per cent of all 384 priests responded. These priests were able to discriminate between so-called "infinite" values and the manner in which they did discriminate is highly consistent with samples of Protestant ministers both in Seattle, Washington and Portland, Oregon. Priests, as might be anticipated, however, manifested greater homogeneity of values than ministers. The findings support the four hypotheses, and, in general, give added weight to the contention that qualitatively unlike values are measurable including those of "infinite" worth. [ABSTRACT FROM AUTHOR]

Viewing diversity as the position of a population along a homogeneity-heterogeneity continuum, a general method is presented for describing diversity within and between groups that are classified by one or more qualitative variables. This method has a wide range of applications, including such phenomena as attitudinal consensus, political cleavage, residential isolation, linguistic communication, cohesion, as well as the general diversity of populations. Diversity is operationally defined as the probability of obtaining unlike characteristics when two persons are randomly paired. Computation of the indexes of diversity within a population, Aw, and between two populations, Ab, is illustrated with data drawn from several substantive areas in sociology. [ABSTRACT FROM AUTHOR]

The article reports on the homogeneity of regression tests. It was observed that the homogeneity of regression assumption in analysis of covariance (ANCOVA) is not being tested by educational researchers. Their recommendation is limited to situations in which the regression is linear. The homogeneity test is not as comprehensive as factorial analysis of variance (ANOVA) and would only detect a limited range of effects. ANCOVA homogeneity test cannot be recommended as an alternative to ANOVA and multiple regression analysis because it will not lead to artifacts when the linearity assumption is violated.

The article presents a study in education which describes the statistical test for homogeneity of regression and presents computational formulas and interpretative in an effort to widen the use of this technique in educational research. The translation from a geometric representation of the phenomenon of homogeneity of regression to an analytic one is obvious to answer questions of parallelity, one considers the regression weights. Also, some diverse examples of experimental and correlation studies where the test has been useful are described.

A conference paper about the biology and classification of phylum sipuncula and echiura is presented. It includes the study of the anatomical homogeneity, behavior, ecology, development, and physiology of the worms. It also investigates the morphological grounds of both phylums and explains the role of the sipunculans in their biotic communities.

Presents the author's opinions on homogeneity related to regression analysis. Discussion on procedures for testing homogeneity of regression; Views on homogeneity of regression as an important assumption for analysis of covariance; Information on degrees of freedom in mathematical statistics; Discussion on analysis of covariance.

A survey by the U.S. Bureau of Labor Statistics reveals that in mid-1950 over five million workers were covered by private pension plans. Since many of these plans were created through collective bargaining, trade unions must bear a heavy part of the responsibility for administering pension programs. William Goldner examines the implications of this responsibility and concludes that it will necessitate "significant and important" changes in trade union structure and functioning. [ABSTRACT FROM AUTHOR]

In testing hypotheses, researchers are almost always faced with the problem of isolating the effect of certain variables. This is a particularly acute problem in the social sciences, where the absence of an experimental environment means that researchers must resort to statistical methods of adjustment. [ABSTRACT FROM PUBLISHER]

The redistricting of Washington State presented an opportunity to apply, with court sanction, a variety of geographic criteria: compactness and regularity; integrity of well-known units (counties and cities); following of natural geographic boundaries; and consideration of functional unity and cultural homogeneity--rather than a political criterion of partisan advantage to particular parties. The existence of two party plans provided an opportunity to measure the effect of such partisanship th rough comparing the operation of differing criteria to the same data. [ABSTRACT FROM AUTHOR]

The article focuses on a study which raises doubts over the assumption that regional cultural differences in the U.S. are declining rapidly and the nation is moving towards a mass homogeneous society. In this study, forty-four national polls on religion, morals, racial and ethnic minorities, international relations, work and political issues and other values and beliefs were used. The findings of the study do not support the supposition that regional differences have declined. On the other hand, the data reveals that many kinds of differences have increased. The study also failed to support the belief that mass media of communication tends to decrease the differences.

The activity of mitochondrial DNA polymerase from Tetrahymerase pyriformis can be induced up to 50-fold by several kinds of DNA damage (irradiation, thymine starvation etc.). The induced mitochondrial enzyme has been purified more than 5900-fold based on whole treated cells. The purification procedure involved the following steps: (a) isolation of mitochondria from cells with induced enzyme; (b) extraction of the polymerase; (c) chromatography on two columns of phosphocellulose at different pH. Homogeneity studies of the purified polymerase indicate that the enzyme is more than 50% pure. The purified polymerase is able to use both native and heat-denatured DNA as primer, although the optimal ion concentrations differ quite considerably with the primer. At low Mg2+ concentrations (5-12 mM) optimal conditions are observed for the reaction with heat-denatured DNA, while the reaction with native DNA primer demonstrates optimum around 45 mM MgCl2. In the reaction with native DNA primer the high MgCl2 concentrations can be partially substituted by high KC1 concentrations of same ionic strength. The reactions with the bihelical polymers poly[d (A-T)] · poly[d (A-T)] and poly[d (I-C)] . poly[d (I-C)] demonstrate optima similar to those found for the reaction with heat-denatured DNA. The purified DNA polymerase has a temperature optimum around 28 °C and heat-inactivation experiments demonstrate that the enzyme is very labile at the high Mg2+ concentrations required for the reaction with native DNA. [ABSTRACT FROM AUTHOR]

The article makes comparison of the relative forecasting capacities of associated econometric structures, leading to conclusions as to the strengths of claims made in their behalf. To compare these models, several constraints and ground rules were established in order to increase the objectivity and fairness of the results. First, the same data period and sample size were used to establish the coefficients in these models. Another constraint in the comparison deals with the admissible information assumed known during the forecasting period. In order to achieve highly comparable predictive comparisons for the model structures, it was necessary to achieve a high degree of alignment among models regarding the information assumed given during the forecast period. A completely ex ante approach was neither possible nor desirable as a basis for testing the models, since it would be next to impossible to separate model predictability from predictability of the unlagged exogenous variables, even if a history of ex ante predictions could be compiled. Thus, the constraint established was homogeneity in the unlagged exogenous variables assumed given during the forecasting period.

This article presents an analysis of production functions with variable elasticity of factor substitution (VES). A powerful index of important properties of a production function is its elasticity of factor substitution function. Under certain assumptions such as first degree homogeneity, the form of the production function is uniquely determined by the form and value of the elasticity of factor substitution function. Production functions generated under the assumption of constant elasticity of factor substitution have been extensively studied both in regard to their theoretical properties and their empirical implications. Once one drops the assumption of constancy and admits a VES, the resultant production function depends on the assumptions involved in the elasticity of factor substitution function. One approach relates the elasticity of factor substitution to capital intensity. It is shown that if the elasticity of factor substitution is a linear function of the capital labor ratio, then a unique explicit production function exists.

The article presents a revised method for grouping sites on the basis of their vegetation. Using frequency modulated relative homogeneity function, the similarities among the sites are calculated and are shown as glyphs on a map because the maps allow a generally precise interpretation of the relations in continua and at community boundaries. The homogeneity function is also used to calculate the centroid and the similarity between community and each site. An illustrative example of using the method is provided. It is concluded that the method can be used where there are large changes in overall abundance from thinly to densely vegetated areas. The study also suggests a way for extending the method to the problem of finding the associated environmental conditions for communities.

The article presents a discussion about the distribution of weed species existing in arable grassland communities. The article provides knowledge about various annual and perennial crops in relation to the usage of animal manures, fertilizers, and environmental factors. An investigation was conducted to certain plant species such as Bonnaya veronicaefolia, Ammania baccifera, Althernanthera sessilis, and Indigofera enneaphylla using the Poisson Formula and diverse frequencies in the plants' relative variance were observed. The article is also supplemented with details on heterogeneity and homogeneity of the species.

Ecological studies have typically employed a frame of reference in which observed phenomena are categorized in terms of bounded territorial units. This has resulted in a number of problems, among them the placement of boundaries, homogeneity within units, comparability between units and the restriction of statistical techniques to those appropriate for sets of nominal categories. it is suggested here that because many social characteristics may vary continuously across the community, the isopleth map may provide a method of relating these to the territory which is, more congruent with their actual rates of variation and which retains a higher level of measurement for the territorial factor. This study examines the extent to which such a map represents a valid image of residential status of areas other than those specifically employed in its construction. The extent to which the isopleth map is congruent with the image of the community held by its residents, and its usefulness in testing research hypothesis are also examined. [ABSTRACT FROM AUTHOR]

Comparisons of total, between-group, and within-group relationship, involving selected socioeconomic characteristics, including delinquency, were made possible by first intercorrelating variables as characteristics of individuals (516 mate, second and third-year high school students in a city of 30,000) and then aggregating individuals into areal or neighborhood units and intercorrelating variables expressed as subgroup means; three levels of aggregation yielded 47, 21, and 10 areal units, each level producing a matrix of between-group correlations. The well-known tendency for between-group r's to be numerically greater than total r's was observed, with the largest increases found for pairs of variables for which within-group homogeneity was highest; also, the effect of increasing aggregate size was to strengthen between-group r's. Using analysis of covariance, within-group regressions were examined in an effort to detect area effects as evidenced by the tendency for certain areas to diverge significantly from the composite within-group relationship; divergent areas were found to possess little or no contextual similarity in terms of SES or geographic proximity. The results obtaining at each level of analysis suggest a number of possible pitfalls related to the "ecological fallacy" issue. [ABSTRACT FROM AUTHOR]

The matching of experimental and control subjects on critical variables, particularly when used in conjunction with random assignment, is widely recognized as a valuable element in research design. Both in discussions of its usefulness and in applications, matching tends to be treated as an attribute. In fact, however, it is a variable, with a range determined by the number and precision of measurement of the items taken into account in the matching process, and by the size and homogeneity of the pool from which subjects are drawn. Failure to distinguish between well-matched and poorly-matched pairs can lead to significant errors of interpretation. But treating the quality of the match itself as a variable, and introducing it into the interpretation can, it is suggested, contribute to the measurement of the effects of the experimental stimulus. An "index of congruence," designed to measure the quality of matching in an experiment in progress, is described. We propose to use this new method as a complement to established statistical techniques, whose comparative advantages and disadvantages are here briefly discussed. [ABSTRACT FROM AUTHOR]

In this article the author propose to examine an hypothesis derived from the field of so-called primitive peoples. It seems to the authors that if they can demonstrate the validity of the continuum in a modem setting the authors shall have made some contribution to any elaboration of the entire theory. The research from which the authors have derived their central hypothesis has been done among so-called primitive societies. It should be noted that the change from a folk to an urban type is essentially analogous to the change from a self-sufficient to a dependent rural community. The essential analogy lodges in the fact that both are changing from more to less homogeneity. As an incident to this study, the authors entertain the hope that the following purposes may be served: a specific understanding of historical process in southern Illinois, a contribution to folk-urban theory, a concrete demonstration of the feasibility of general law in the field of society, whether primitive or modern and a greater rapprochement between the disciplines of anthropology and sociology.

The article comments on the impacts of the war on the rural community in the U.S. Different communities react in different ways, depending among other things upon the section of the country, the degree of rurality, the homogeneity of the population, and the proximity of centers of war activity such as munitions plants and military reservations. In general, however, people can conclude that the more strictly rural areas have been somewhat slower than urban areas to become aroused to the grim realities of total war. However, even the residents of the more isolated rural communities are now beginning to feel the full impacts of the national crisis and are responding rapidly to the national need. That their response has been somewhat slow is no reflection on their patriotism or intelligence. It is a natural consequence of their relative isolation and reflects in part the slowness in which war programs have been coordinated to permit maximum participation. That the war has had a tremendous effect on the rural U.S. no one can deny. It is difficult, however, after a year at war to know just what the effects are and what adjustments are being made to meet the war impacts.

One hundred ten small communities, all of which had voted on the question of discontinuing their high schools, were studied to determine the relationship between community homogeneity and this community decision. Contrary to expectations, ethnically homogeneous communities displayed less opposition to the loss of their high schools than did heterogeneous communities. This finding was considered to be a reflection of the greater degree of integration in homogeneous communities. [ABSTRACT FROM AUTHOR]

Comments on an article published in the 1970 issue of the "American Educational Research Journal" focusing on the topic of homogeneity of regression. Use of standard multiple regression programs to find test statistics; Description of the sum of squares formed from estimating regression equation; View that deviation scores should be used to form the cross product matrices.

The article reports on homogeneity of regression. The author investigates the test, its applications and its place in the statistical methodology. The author questions the article with errors being published in a reputable journal and says that this is a serious matter specially when one considers the purpose of the article that is to translate known statistical procedures for audience of educational researchers. Incorrect test statistics is the result of procedures advocated by the authors. The purpose is not served in the article and gives a disservice to the audience it wants to enlighten.