Tuesday, February 28, 2017

Digging Deeper: Probability Space & Euclidean Space

“Measure Theory becomes Probability Theory when Euclidean Space becomes Probability Space”

In probability theory we model the probability of a complex real phenomenon that is random in nature. Probability of occurrence of outcomes of such phenomenon is dependent on several variables that are also random in nature. This can be explained by a multidimensional Euclidean Space with one coordinate axes being the probability; this probability is a function of these multiple random variables. So a multi-dimensional probability space has to be mentally visualized.  If there is only one variable then the probability space becomes a two dimensional Euclidean space

As we go closer and closer to predicting the complexity of real life phenomenon by computing its probability, the simple formula of favorable cases/total cases takes an entirely new form. This form is governed by axioms of probability theory which can be closely linked to measure theory. For a two dimensional probability space computation of probability for a continuous random variable is equal to finding an area. This is done using simple integration, as shown figure above. Please refer to blog of 26 Feb 2017 for the details of these figures. For a three dimensional space it is a volume and we use double integrals to find this volume. But for n dimensional space, it is Lebesgue measure (measure theory) that aids in computation of the n dimensional volume. For ease of graphical representation the figure below shows a three dimensional space.

No comments:

Post a Comment