Changes

*In a normal distribution the mean =0 and standard deviation =1,then  the distribution is called the standard normal distribution or the unit normal distribution, and a random variable with that distribution is a standard normal deviate.

*In a normal distribution the mean =0 and standard deviation =1,then  the distribution is called the standard normal distribution or the unit normal distribution, and a random variable with that distribution is a standard normal deviate.

*It is the only absolutely continuous distribution.

*It is the only absolutely continuous distribution.

*A normal distribution is calculated by  

*A normal distribution is calculated by :

<math>f(x,\mu,\sigma)=\frac {1}{\sigma\sqrt{2\pi}} e^{\frac{-(x-\mu)^2}{2\sigma^2}}</math>,

<math>f(x,\mu,\sigma)=\frac {1}{\sigma\sqrt{2\pi}} e^{\frac{-(x-\mu)^2}{2\sigma^2}}</math>

where <math>\mu</math> is the mean and  <math>\sigma<\math> is the standard deviaton of the distribution.

where <math>\mu</math> is the mean and  <math>\sigma<\math> is the standard deviaton of the distribution.