Some approaches to statistical analysis of a weather modification experiment

Data from a weather modification experiment are examined and a number of statistical analyses reported. The validity of earlier inferences is studied as are the utilities of various statistical methods. The experiment is described. The original analysis of North American Weather Consultants, who conducted the experiment, is reviewed. Data summarization is reported. A major approach to analysis is through the use of cloud-physics covari-ates in regression analyses. Finally, a multivariate analysis is discussed. It appears that the covariates may have been affected by treatment (cloud seeding) and that their use is invalid, not only reducing error variances but removing treatment effect. Some recommendations for improved design of similar future experiments are given in a concluding section, including preliminary trial use of blocking by storms.     

Measuring Pupil Activity

After the end of World War I, Congress enacted a bill that would reward military veterans for their service. The bill provided the veterans cash bonuses that would be paid starting in 1945. But as the nation settled into the Great Deression these veterans began to clamor for payment of their bonuses. In May of 1932, and estimated 15,000 veterans and their families made their way to Washington D. C. The events of the “Bonus Army” provide the basis of a lesson for students to examine the plight of these veterans and the eventual response of the federal government to later pass the GI Bill of Rights.     

Social Network Analysis for Analyzing Groups as Complex Systems

ABSTRACT

The introduction and application of social network analysis, a method seen as superior to experimental or single-system research design for showing group change, examined group dynamics and change over time using a hypothetical example of an Internet group for gays and lesbians. Rather than utilizing traditional definitions of independent and dependent variables, the analysis utilized hypothetical data with nodes or individuals, ties, and the relationships they formed. The recently developed computer program NodeXL provided diagrams and statistics that demonstrated node and tie variation and individual and group development over time. Discussion demonstrated the utility of such diagrams for research and practice.     

Community Organization and Administration

The author argues that when minority content has been included in the social work curriculum, the affective domain of cross-cultural study has been bypassed in favor of cognitive mastery. This article presents a conceptual system for evaluating students' progress in the affective area as a way of preparing them for the demands of cross-cultural practice and as a step toward creating a confluence between content and process.     

On the Use of Hierarchical Probabilistic Models for Characterizing and Managing Uncertainty in Risk/Safety Assessment

A general probabilistically-based approach is proposed for both cancer and noncancer risk/safety assessments. The familiar framework of the original ADI/RfD formulation is used, substituting in the numerator a benchmark dose derived from a hierarchical pharmacokinetic/pharmacodynamic model and in the denominator a unitary uncertainty factor derived from a hierarchical animal/average human/sensitive human model. The empirical probability distributions of the numerator and denominator can be combined to produce an empirical human-equivalent distribution for an animal-derived benchmark dose in external-exposure units.