Mann-Whitney test is not just a test of medians: differences in spread can be important

Abstract

death follows the withdrawal of ventilatory support, however, you could argue that death must be the intended result and not merely a side effect of acting in the patient's best interests. This is because paralysing drugs suppress a patient's breathing for some time after an infusion has been stopped. Because the patient completely depends on the ventilator she dies quickly when it is withdrawn. The BMA suggests that withdrawing respiratory support in these circumstances could be interpreted in law as an intended killing. 3The doctrine of double effect is difficult to apply in this case, not impossible. To avoid confusion it is necessary to deal with each decision in turn. The first decision-to use muscle relaxants-itself has dual effects, the intended one being to make ventilation possible, and the side effect being to make the patient completely dependent on it. The second decision-to withdraw ventilation-has the effect that the patient dies quickly, but this doesn't have to be the intended effect. The two decisions are morally independent, despite being chronologically and logically sequential, because the intention behind the first decision (to make ventilation possible) is not linked to the side effect of the second, the patient dies. This could be an accurate description of the doctor's intentions in the face of difficult circumstances. It could also provide a legal defence against the charge of murder, although I know of no case law testing this interpretation.The alternative would be either to continue respiratory support indefinitely or to stop the paralysing drugs first and wait for any effects to wear off completely before withdrawing ventilation. The first is arguably not in the patient's best interests. The other may prolong the patient's suffering and that of her parents because of the delay between deciding to withdraw life prolonging treatment and actually doing it. The only reason why muscle relaxants were used in the first place was to allow ventilatory support, so the intention behind withdrawing it can only be to allow the subsequent withdrawal of ventilation, thereby linking the intention of the first decision with the effect of the second. The patient may become distressed and, without the effect of the muscle relaxants, the ventilator may not work properly anyway. It is difficult to see how withdrawing muscle relaxants can be in a patient's best interests without taking him or her off the ventilator at the same time.In any case there are drugs, such as atracurium, that do not have these problematic residual effects, making this particular moral difficulty disappear.

Relações solo-vegetação na estruturação de comunidades de cerrado sensu stricto no sul de Minas Gerais, Brasil

“…Para determinação dos processos de estruturação das comunidades, os atributos edáficos das duas classes pedológicas levantadas foram comparados pelo teste estatístico de MannWhitney a 5% de confiança (Hart 2001). Ainda com objetivo de identificar tais mecanismos ecológicos, os parâmetros de densidade de indivíduos e área basal por hectare, bem como médias de diâmetro (C30) e de alturas dos diferentes subtipos de cerrado sensu stricto também foram submetidos ao mesmo teste estatístico (Hart 2001). Por fim, para correlacionar os parâmetros de solo e a abundância de espécie, utilizou-se a análise de correspondência canônica -CCA (Ter Braak 1987) do software PC-ORD 5.0 (McCune & Mefford 1999).…”

Impact of metoprolol on insulin sensitivity in the ICU

“…Insulin sensitivity values were compared using cumulative distribution functions (CDFs) and the Mann-Whitney U-test for statistical significance. CDFs present the entire shape of the distribution, which was particularly useful for these skewed data sets (Hart, 2001). Pvalues of less than 0.05 were considered significant.…”

A Independência da Escolha dos Canais de Marketing nas Rendas dos Produtores Orgânicos Americanos

“…A análise por meio da variável renda é relevante para determinar o tamanho da propriedade e, assim, classificar pequenas e grandes propriedades. O teste de Mann-Whitney é usado para comparar as diferenças entre os dois grupos independentes quando a variável dependente é ordinal ou contínua, mas que não são normalmente distribuídas (HART, 2001).…”