LogNormal

Transform > Probability Distributions > LogNormal

 

Calculates the probability densities, cumulative probabilities, and inverse cumulative probabilities for a LogNormal distribution.

The lognormal distribution is the distribution of a random variable whose logarithm is normally distributed. If Y is a random variable with a normal distribution, then the random variable X = exp(Y) has a lognormal distribution. Likewise if the random variable X has a lognormal distribution then the random variable Y = log(X) is normally distributed.

 

noteNOTE: When specifying the parameters that describe an instance of LognormalDistribution we do so by specifying the mean and standard deviation of its logarithm which, by definition, is normally distributed.

 

 

 

Dialog box items

Source Column:
Enter the column you want to evaluate.

Target Column:
Enter a storage column for the generated values. Leave blank to have VisualStat automatically name the target column.

Statistics:
Choose from the following options:

oProbability density: Choose to calculate the probability densities.

oCumulative probability: Choose to compute the cumulative probabilities.

oInverse cumulative probability: Choose to compute the inverse of the cumulative probabilities.

Distribution: Select the distribution for the variable.

Mean: Enter the mean value you want to use as the center point for the lognormal distribution.

Standard deviation: Enter the standard deviation you want to define the lognormal distribution.

 

 

Example

Example of using the probability density function (pdf)

 

 

 

See Also:


Probability Distributions

Web Resource: Weisstein, Eric W., Wolfram MathWorld. | Wikipedia