Testing for Equivalence of Means under Heteroskedasticity by an Approximate Solution of a Partial Differential Equation of Infinite Order

Abstract. A test for two‐sided equivalence of means has been developed under the assumption of normally distributed populations with heterogeneous variances. Its rejection region is limited by functions ± h that depend on the empirical variances. h is stated implicitly by a partial differential equation, an exact solution of which would provide a test that is exactly similar at the boundary of the null hypothesis of non‐equivalence. h is approximated by Taylor series up to third powers in the reciprocal number of degrees of freedom. This suffices to obtain error probabilities of the first kind that are very close to a nominal level of α = 0 . 05 at the boundary of the null hypothesis. For more than 10 data points in each group, they range between 0.04995 and 0.05005, and are thus much more precise than those obtained by other authors.     

Migration Theories and First Nations Mobility: Towards a Systems Perspective*

Au Canada, la recherche sur la migration des autochtones vers les centres urbains a mis en avant l'importance de facteurs économiques, les mou‐vements de retour étant expliqués comme un échec lié aux difficultés d'adaptation. Les facteurs sous‐tendant la migration vers les villes ont été peu étudiés, et des études récentes ont mis l'accent sur l'ampleur des mouvements plutôt que sur d'autres théories. Cet article suggère des voies selon lesquelles on peut avoir recours à une approche systémique pour intégrer des facteurs des contextes politique, économique et social ainsi que des liens individuels, institutionnels et de culture de masse. The migration of Canadian Aboriginal people to cities has usually been understood as economically motivated, with return migration to Aboriginal communities resulting primarily from failure to adapt to urban life. However, the reasons underlying migration have rarely been directly addressed, and recent studies of migration have focussed on the size of flows, rather than relating this migration stream to theories of migration developed in other contexts. This paper suggests ways in which a systems perspective on migration can be used to incorporate elements of the political, economic and social context, as well as individual, institutional and mass culture links between the two areas.     

From Parties to Candidates: Examining the Role of the Media

This article examines the relationship between campaign mediaexpenditures and the saliency of attitudes about parties andcandidates in the electorate using data from the 1978 NationalElection Study and the Traugott/Goldenberg study of campaignmanagers. A negative relationship is found between media spendingand party saliency. In contrast, a strong positive correlationis shown to exist between media expenditures and candidate saliency.These relationships are found to be accentuated when the partyorganizations in the congressional district are weak and wherepolitical action committees contribute a large proportion ofthe total campaign expenses.     

Adoptions in West Germany: Attitudes of Social Workers

Correspondence to Dr Martin R. Textor, Hessstrasse, D-8000 München 40, Germany. Summary After a short overview of adoption services in Germany, thelegal situation, and the number of adoptions the results ofinterviews with 117 social workers arc presented. All of themwere responsible for adoptions and worked at agencies of localauthorities or welfare organizations in Bavaria. Their attitudestowards adoption as an alternative to abortion, towards birthmothers, adoptive families, searching adoptees, internationaladoptions, open adoptions, and the placement of children arcexplored. It was found that the attitudes were very heterogeneousand that they had changed during the last 20 years: The respondentsespoused a more positive view of birth mothers and searchingadoptees, considered uncommon groups of applicants (e.g. singles,remarried couples) and children (e.g. handicapped or older ones)for adoption, and took a more positive stance towards half openand open forms of adoption. They did not see adoption as analternative to abortion, were against private adoptions, andstrove for more open forms of adoption.