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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,660

Statistics Formulas

**Average (mean)**:

**Binomial Probability Mass Function**

The probability of getting exactly k successes out of n events where the probability of k on each event is p:

Mean:

Variance:

Standard deviation:

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 23,086

**Poisson Distribution**

Poisson distrubtion is the limiting form of the Binomial Distribution when n, the number of trials is very large, and p, the probability of success, is very small, np remains finite.

Let

A random variable X taking values 0,1,2 .. is said to have a Poisson distribution with parameter

if its proabability distribution is given by

where r=0,1,2....

The mean of the Poisson Distribution

The variance of the Poisson Distribution

The mean and the variance of the Poisson Distribution is equal to

.It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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**Daniel123****Member**- Registered: 2007-05-23
- Posts: 663

**Product Moment Correlation Coefficient (PMCC)**

**The least squares regression line**

y = a + bx

andWhere

*Last edited by Daniel123 (2008-03-22 13:32:39)*

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**Daniel123****Member**- Registered: 2007-05-23
- Posts: 663

**Normal Distribution Function**

*Last edited by Daniel123 (2008-04-15 08:14:04)*

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**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 23,086

Standard Deviation

where

and is the mean.

Standard Deviation

where d = x - A, where A is the Assumed mean.

Standard Deviation for Discrete series:

In discrete series when deviations are taken from Arithmetic Mean,

where

and is the mean.

When deviations are taken from Assumed mean,

where d = x - A and A is the Assumed mean.

Variance

Variance is the square of Standard Deviation. The positive square root of the variance is defined as Standard Deviation.

Standard Deviation for the first 'n' Natural numbers is

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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