For all those who believe in the calling of Destiny and the theory "Everything happens for a reason" have been absolutely right all this while. Infact the journey of our lives is no more in the realms of blind faith & empty belief .. everything in our life truly happens for a reason, but that reason is neither supernatural

*divinity*or

*fate*.

It happens because of a mysterious statistical phenomenon called "

*".*

**Regression towards the Mean**Yes.. Ladies & Gentlemen.. the answer to our lives trial is not the mightly Soul but mundane Statistics. And our lives and all that happens in it is governed by the laws of statistics. Similar to the physical objects that follow the law of physics.

* Everything in life.. regresses towards the mean*.

What exactly is regression toward the mean -

Shaughnessy and Zechmeister (1990) said that regression toward the mean is a phenomenon that is similar to several everyday expressions such as "law of averages", "things will even out" or "we are due for a good day after a string of bad ones". And one that I would like to add is "it can't possibly get worse (or better) than this!" Basically what all these phrases are saying is that "extreme experiences tend to be balanced by less extreme experiences"

Infact by now I am so used to the fact that a **Terrific** year will be followed by a couple of **Terrifying** years. After all the law of regression to the mean is inescapable.

Consider a simple example: a class of students takes a 100-item true/false test on a subject. Suppose that all students choose randomly on all questions. Then, each student’s score would be a realization of one of a set of i.i.d. random variables, with a mean of 50. Naturally, some students will score substantially above 50 and some substantially below 50 just by chance. If one takes only the top scoring 10% of the students and gives them a second test on which they again choose randomly on all items, the mean score would again be expected to be close to 50. Thus the mean of these students would “regress” all the way back to the mean of all students who took the original test. No matter what a student scores on the original test, the best prediction of his score on the second test is 50.

If there were no luck or random guessing involved in the answers supplied by students to the test questions then all students would score the same on the second test as they scored on the original test, and there would be no regression toward the mean.

But all of us have lived long enough to know .. Luck plays a vital role in ones life.. far more that what we openly acknowledge. However regression to the mean would ential that all of us would have fairly the same level of luck if cummulated from cradle to grave.

The concept of regression comes from genetics and was popularized by Sir Francis Galton during the late 19th century with the publication of Regression towards mediocrity in hereditary stature. Galton observed that extreme characteristics (e.g., height) in parents are not passed on completely to their offspring. Rather, the characteristics in the offspring regress towards a mediocre point (a point which has since been identified as the mean).

Although Galton popularized the concept of regression, he fundamentally misunderstood the phenomenon; thus, his understanding of regression differs from that of modern statisticians as follows: Galton observed correctly that the characteristics of an individual are not determined completely by their parents; there must be another source. However, his explanation is that “A child inherits partly from his parents, partly from his ancestors. In other words, Galton saw regression toward the mean as simply an inheritance of characteristics from ancestors that are not expressed in the parents; he did not understand * regression to the mean as a general statistical phenomenon*. In contrast to this view, it is now known that regression towards the mean occurs in all bivariate normal distributions.

So now you know the reason 'why everything happens for a reason" because life tends to regress towards the mean and it ensures that each one of us has fair share of glory & agony. By the time we hit the grave the our life's balance sheet of happiness & sorrow is balanced towards the mean value of entire humanity. Infact Hindu philosophy has taken the concept to the next level by incorporating that bad deeds done in this life would have to paid for by misfortune in the next life. Well "Regression to the mean" is inescapable even in afterlife. And it might be likely that the Toaist philosophy of Yin-Yang is derieved by the observation that everything in life tends to regress to the mean.. the balance between day & night, darkness & light.

If you need any more information please contact the nearest Statistician. For online help follow the links from where I have borrowed most of the verbiage for this blog. Regression source 1 Regression source 2 Regression source 3

## 4 comments:

AWESOME and I ABSOLUTELY agree with what u !!

Well Destiny --yes--we all do say that everything happens for a reason and repent on it when things go wrong..kya kare...yeh saali zindagi....we have to live with it right. U & Mridu know my case ....but we need to get out of it ..All i would say is do not look back and grieve over the past for it is gone; and do not be troubled about the future, for it has not yet come. Live in the present, and make it so beautiful it will be worth remembering.

In the same lines we have a saying in Tamil that states "For continuous 5 generation there is no family that has lived extremely prosperous and for 5 generation there is no family that has been very poor,it will balance"

--Vasuki

Absolutely true Vasuki .. regression of the mean across multiple lives is exactly how Hindu philosophy explains the concepts of rebirths .. and guess this Tamil saying is another way of explaining the same :-)

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