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R-squared for Decision Tree

@machinelearnbot

I use the methodology you speak of all the time. I was the original programer for Breiman and Stone's version of CART in the late 70's which is where I believe I was first introduced to that method. However we were very careful to use the term variation explained since there is little relationship to the theoretical Pearson "r". Be aware that this value can go negative. Which implies that parts of your model behave a lot higher variation then the population variance.


[Report] Precipitation drives global variation in natural selection

Science

Climate change has the potential to affect the ecology and evolution of every species on Earth. Although the ecological consequences of climate change are increasingly well documented, the effects of climate on the key evolutionary process driving adaptation--natural selection--are largely unknown. We report that aspects of precipitation and potential evapotranspiration, along with the North Atlantic Oscillation, predicted variation in selection across plant and animal populations throughout many terrestrial biomes, whereas temperature explained little variation. By showing that selection was influenced by climate variation, our results indicate that climate change may cause widespread alterations in selection regimes, potentially shifting evolutionary trajectories at a global scale.


How Colors in Business Dashboards Affect Users' Decision Making

Communications of the ACM

Business dashboards help users visually identify trends, patterns, and anomalies in order to make effective decisions.1 Dashboards often use a variety of colors to differentiate and identify objects.2 Although using colors might improve visualization, overuse or misuse can distract users and adversely affect decision making. The bar charts in Figure 1 reflect sales of office-supply products. The bars in the left-hand chart are uniform in color, and the relative height is the only salient information source. However, the chart on the right uses a different color for each bar, and the variation in both height and color could be perceived as different information.


Planning for a rise

Science

Coastal areas affected by rising seas are subject to regional variations in sea level, as well as the global mean rise. In fact, local effects that occur over decades, rather than centuries, can be several times larger than the global one. Nieves et al. provide a tool to help coastal planners estimate the magnitudes of these regional sea level variations. They show that upper ocean temperature is a key indicator of changes in short-term sea level rise over large coastal regions of the United States. This information should enable more informed adaptation over time scales relevant to decision-makers.


Normative brain size variation and brain shape diversity in humans

Science

Brain size variation over primate evolution and human development is associated with shifts in the proportions of different brain regions. Individual brain size can vary almost twofold among typically developing humans, but the consequences of this for brain organization remain poorly understood. Using in vivo neuroimaging data from more than 3000 individuals, we find that larger human brains show greater areal expansion in distributed frontoparietal cortical networks and related subcortical regions than in limbic, sensory, and motor systems. This areal redistribution recapitulates cortical remodeling across evolution, manifests by early childhood in humans, and is linked to multiple markers of heightened metabolic cost and neuronal connectivity. Thus, human brain shape is systematically coupled to naturally occurring variations in brain size through a scaling map that integrates spatiotemporally diverse aspects of neurobiology.