See how humans have redrawn Earth's biological map

Humans are rapidly changing the distinctive biodiversity that evolved in regions of the Earth over millions of years by introducing new species and wiping out others, a new study has shown.

Ants maintain essential interactions despite environmental flux

Ants adjust their social interactions to accommodate changes in population density, according to researchers at Penn State and Georgetown University. The findings suggest that ant colonies are capable of maintaining their ...

Fish diversity linked to Caribbean coral reef health

The health of coral reefs can be impacted as much by the diversity of fish that graze on them as by the amount of fish that do so, according to a new study by scientists at Bigelow Laboratory for Ocean Sciences. In the Science ...

Is climate change already making hurricanes stronger?

Scientists generally agree that, by the year 2100, climate change will most likely make hurricanes stronger. But what about the hurricanes of this year and next—is climate change already worsening those? The science is ...

Complete world map of tree diversity

Biodiversity is one of Earth's most precious resources. However, for most places in the world, scientists only have a tiny picture of what this diversity actually is. Researchers at the German Centre for Integrative Biodiversity ...

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Statistical model

A statistical model is a set of mathematical equations which describe the behavior of an object of study in terms of random variables and their associated probability distributions. If the model has only one equation it is called a single-equation model, whereas if it has more than one equation, it is known as a multiple-equation model.

In mathematical terms, a statistical model is frequently thought of as a pair (Y,P) where Y is the set of possible observations and P the set of possible probability distributions on Y. It is assumed that there is a distinct element of P which generates the observed data. Statistical inference enables us to make statements about which element(s) of this set are likely to be the true one.

Three notions are sufficient to describe all statistical models.

One of the most basic models is the simple linear regression model which assumes a relationship between two random variables Y and X. For instance, one may want to linearly explain child mortality in a given country by its GDP. This is a statistical model because the relationship need not to be perfect and the model includes a disturbance term which accounts for other effects on child mortality other than GDP.

As a second example, Bayes theorem in its raw form may be intractable, but assuming a general model H allows it to become

which may be easier. Models can also be compared using measures such as Bayes factors or mean square error.

This text uses material from Wikipedia, licensed under CC BY-SA