# Manuals/calci/NORMAL

NORMALDISTRIBUTED(x,m,sd)

• is the value for which distribution is evaluated.
• is the mean.
• is the standard deviation.

## Description

• This function gives the value of the normal probability distribution.
• It is the continuous probability distribution.
• The normal distributions are a very important class of statistical distributions.
• All normal distributions are symmetric and have bell-shaped density curves with a single peak.
• The term bell curve is used to describe the mathematical concept called normal distribution.
• It is also called as Gaussian distribution.
• The Normal Distribution has: mean = median = mode
• i.e., This distribution is symmetry about the center.
• Half of values less than the mean and half of values greater than the mean.
• In a normal distribution the probability values are satisfying the following conditions:
 1. The total area under the curve is equal to 1 (100%)
2. About 68% of the area under the curve falls within 1 standard deviation.
3. About 95% of the area under the curve falls within 2 standard deviations.
4. About 99.7% of the area under the curve falls within 3 standard deviations.

• 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.
• A normal distribution is calculated by :

where is the mean and is the standard deviaton of the distribution.

## Examples

1. =NORMALDISTRIBUTED(250,255,2.5) = 748.545737759758,417.93831835416444,-92.67846228553037,etc
2. =NORMALDISTRIBUTED(30,36,20.9) = 7.937852412035841,10.385286729354199,83.54572095198611 etc.

NORMAL