Citat:
În prealabil postat de flying
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Aham.
Apropo, exista o corelatie statistica intre casatorie si divort.
Astfel, s-a stabilit, ca principala cauza a divortului este casatoria.
Inca nu s-a gasit nici macar o singura persoana care sa divorteze fara sa fie castorita in prealabil.
Limitations
This study examined aggregate data, which introduced
at least four limitations.
(1) Since
the dependent variable was a percentage, the regression analysis showed association, not causation. If individual children had been
examined, the dependent variable might have been 1 if the child developed autism or speech disorder and 0 otherwise. The results of such a regression could have been used to predict health outcomes for children not in the study. However, such analysis is beyond the scope of this study.
(2) The data in this study were not exact. Learning disability classifications were assigned by individual school districts, which may have implemented classifications differently; vaccination proportions were based on limited surveys, not entire populations.
(3) Aggregation bias assumes each individual in a given group acts according to the average of the group, but that is rarely the
case. In this study, children in each U.S. state were divided into two groups, fully vaccinated and not fully vaccinated. However, the variation among the not fully vaccinated children was not known. Even if a child missed only one shot in the series, that child was classified as not fully vaccinated. A child who missed only one shot was different from a child who was completely unvaccinated, yet in this study both children were classified as not fully vaccinated.
(4) Confounding factors were also an issue. Factors such as prenatal exposure to toxins (Austin 2008) and toxin exposure from
sources other than vaccines (Palmer et al. 2006; 2009) were not considered yet might influence whether a child develops autism. Although the study found that, on average, children who were not fully vaccinated were less likely to develop autism or speech disorders, any given child—especially a child who was almost fully vaccinated or was exposed to toxins in utero—may have developed the disabilities.
As a result of “ecological fallacy”—applying results from the study of aggregate populations to individuals—epidemiological studies such as this one are better for creating hypotheses than for establishing causation (Washio et al. 2008).
Sau in varianta facila pentru cei care nu pricep engleza sau nu inteleg ce este scris: studiul este un joculet statistic cu limitari severe, pe scurt: apa de ploaie.