title: Tendency toward negative correlations for positively-skewed independent random variables

authors: Bardsley, W. Earl

subjects: correlation coefficient

abstract: Hydrological variables often display positive skewness, with means exceeding medians. Even when two such variables are independent, there is a more than 50% chance that a bivariate random sample will yield a negative value of the Pearson product-moment linear correlation coefficient r. Simulations from inverse Gaussian distributions suggest that this effect is small and unlikely to have any effect on significance tests of r if two skewed variables are in fact independent. However, a high frequency of negative sample correlations in a multi-site hydrological study could result in an incorrect deduction that some weak but widespread physical process is in operation.

text: Tendency toward negative correlations for positively-skewed independent random variables Hydrological variables often display positive skewness, with means exceeding medians. Even when two such variables are independent, there is a more than 50% chance that a bivariate random sample will yield a negative value of the Pearson product-moment linear correlation coefficient r. Simulations from inverse Gaussian distributions suggest that this effect is small and unlikely to have any effect on significance tests of r if two skewed variables are in fact independent. However, a high frequency of negative sample correlations in a multi-site hydrological study could result in an incorrect deduction that some weak but widespread physical process is in operation.

year: 2014

title: Constellations with range and IS-categories

authors: Gould, Victoria

abstract: Constellations are asymmetric generalisations of categories. Although they are not required to possess a notion of range, many natural examples do. These include commonly occurring constellations related to concrete categories (since they model surjective morphisms), and also others arising from quite different sources, including from well-studied classes of semigroups. We show how constellations with a well-behaved range operation are nothing but ordered categories with restrictions. We characterise abstractly those categories that are canonical extensions of constellations with range, as so-called IS-categories. Such categories contain distinguished subcategories of insertions (which are monomorphisms) and surjections (in general different to the epimorphisms) such that each morphism admits a unique factorisation into a surjection followed by an insertion. Most familiar concrete categories are IS-categories, and we show how some of the well-known properties of these categories arise from the fact that they are IS-categories. For appropriate choices of morphisms in each, the category of IS-categories is shown to be equivalent to the category of constellations with range.

text: Constellations with range and IS-categories Constellations are asymmetric generalisations of categories. Although they are not required to possess a notion of range, many natural examples do. These include commonly occurring constellations related to concrete categories (since they model surjective morphisms), and also others arising from quite different sources, including from well-studied classes of semigroups. We show how constellations with a well-behaved range operation are nothing but ordered categories with restrictions. We characterise abstractly those categories that are canonical extensions of constellations with range, as so-called IS-categories. Such categories contain distinguished subcategories of insertions (which are monomorphisms) and surjections (in general different to the epimorphisms) such that each morphism admits a unique factorisation into a surjection followed by an insertion. Most familiar concrete categories are IS-categories, and we show how some of the well-known properties of these categories arise from the fact that they are IS-categories. For appropriate choices of morphisms in each, the category of IS-categories is shown to be equivalent to the category of constellations with range.

year: 2022

title: Whānau Māori explain how the Harti Hauora Tamariki tool assists better access to health services

authors: Masters-Awatere, Bridgette

abstract: In this paper whānau Māori highlight how a Kaupapa Māori centred intervention (the Harti Hauora Tamariki tool) has improved interactions with health services. The Harti tool is undergoing a Randomised Control Trial at Waikato Hospital in New Zealand. As part of the RCT, the authors engaged in a series of qualitative interviews with whānau members of tamariki Māori (children aged 0-5years) admitted to Waikato Hospital’s paediatric ward. Whānau who met at least one criteria for New Zealand’s domains of deprivation were included. Using a Kaupapa Māori approach to the study, participants shared their views on barriers and facilitators to accessing health resources and primary care services. Our interviews highlight how the Harti tool, when administered in a culturally appropriate and respectful manner that prioritised relationship-building, enabled better connection to healthcare services. Prevalent in our analysis were connections to wider determinants of health and ways to reduce existing health inequities. To conclude the paper, we highlight how the tool has enhanced feelings of being in control of health with the potential to reduce the likelihood of a hospital readmission.

text: Whānau Māori explain how the Harti Hauora Tamariki tool assists better access to health services In this paper whānau Māori highlight how a Kaupapa Māori centred intervention (the Harti Hauora Tamariki tool) has improved interactions with health services. The Harti tool is undergoing a Randomised Control Trial at Waikato Hospital in New Zealand. As part of the RCT, the authors engaged in a series of qualitative interviews with whānau members of tamariki Māori (children aged 0-5years) admitted to Waikato Hospital’s paediatric ward. Whānau who met at least one criteria for New Zealand’s domains of deprivation were included. Using a Kaupapa Māori approach to the study, participants shared their views on barriers and facilitators to accessing health resources and primary care services. Our interviews highlight how the Harti tool, when administered in a culturally appropriate and respectful manner that prioritised relationship-building, enabled better connection to healthcare services. Prevalent in our analysis were connections to wider determinants of health and ways to reduce existing health inequities. To conclude the paper, we highlight how the tool has enhanced feelings of being in control of health with the potential to reduce the likelihood of a hospital readmission.

year: 2019