Class,race, and the disposal of urban waste: Locations of landfills,incinerators, and sewage treatment plants

This study compared the socioeconomic status, racial composition, and ethnic composition of 49 randomly selected U.S. cities with those of the census tracts containing the solid waste disposal facilities and sewage treatment plants for those cities. Contrary to the environmental racism and classism hypotheses, residents of tracts with landfills or incinerators had higher incomes and were less likely to be minority group members than residents of the cities that generated the refuse—although they did have somewhat lower education levels. There were few differences between the population characteristics of the cities and the census tracts that contained their sewage treatment plants. Possible explanations for these findings are discussed.     

A Sample Size Formula for a Non-Central t Test

An elementary method of proof of the mode, median, and mean inequality is given for skewed, unimodal distributions of continuous random variables. A proof of the inequality for the gamma, F, and beta random variables is sketched.     

Editor's Report

There are two common methods for statistical inference on 2 × 2 contingency tables. One is the widely taught Pearson chi-square test, which uses the well-known χ²statistic. The chi-square test is appropriate for large sample inference, and it is equivalent to the Z-test that uses the difference between the two sample proportions for the 2 × 2 case. Another method is Fisher’s exact test, which evaluates the likelihood of each table with the same marginal totals. This article mathematically justifies that these two methods for determining extreme do not completely agree with each other. Our analysis obtains one-sided and two-sided conditions under which a disagreement in determining extreme between the two tests could occur. We also address the question whether or not their discrepancy in determining extreme would make them draw different conclusions when testing homogeneity or independence. Our examination of the two tests casts light on which test should be trusted when the two tests draw different conclusions.     

A Phenomenological Study of Postdivorce Adjustment in Midlife

Today, 50% of all U.S. marriages are expected to end in divorce, with the majority of the divorces being granted to individuals between the ages of 45 and 54. Gaining an understanding of the lived experience of postdivorce adjustment as seen in midlife was the aim of this study. A phenomenological research design was used. The themes that emerged from the data included time, emotional pain, changes in postdivorce parenting, and a sense of starting over. The clinical implications of this study suggest that obtaining an understanding of the postdivorce adjustment experience might help mental health practitioners enhance care for divorced individuals, divorcing couples, and their family members.     

The Early Development Instrument: An Examination of Convergent and Discriminant Validity

The convergent and discriminant validity of the Early Development Instrument (EDI), a teacher-rated assessment of children’s “school readiness”, was investigated in a multicultural sample of 267 kindergarteners (53% male). Teachers evaluations on the EDI, both overall and in five domains (physical health/well-being, social competence, emotional maturity, language/cognition, communication/general knowledge), were related to direct, child-based assessments of performance on two standardized measures of school readiness, and measures of phonological awareness and early social competence. Regression analysis indicated that together the four comparison measures accounted for 36% of variance in overall EDI scores, each making a significant and unique contribution. Results supported the convergent validity of overall EDI scores but not the discriminant validity of EDI domain scores. Moreover, correlations between EDI scores and comparison measures varied widely across teachers, suggesting considerable individual differences in teacher’s ability to evaluate school readiness relative to direct, child-based assessments, and confirming that the EDI is more appropriate for deriving inferences at higher aggregated levels such as community or region. The validation of EDI domain scores remains an important challenge in future research.     

Value Accentuation or Convergence: Analysis of the Pattern and Process of College Student Change

Abstract

College student value change was analyzed for individual and group value accentuation or convergence among a longitudinal panel study of students in a traditional, large liberal arts college and a small, innovative living-learning subenvironment. Initially students in the innovative environment were more liberal, socally conscious, culturally sophisticated and intellectually oriented than their counterparts in the traditional setting, and, after two years, accentuation of these group differences had occurred. However, these group differences were not the result of accentuation of individual differences. Instead, increases in the student values were linked to interaction with peers and faculty on related topics and these patterns of interaction were more likely to occur in the living-learning subenvironment. Finally, those students who initially were lowest on a value and who frequently interacted with faculty or peers on related topics tended to experience the greatest value change.