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Download a pdf copy of this help file here |
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Download a pdf copy of this help file here |
Format: VoseLognormalAlt(value1, probability1, value2, probability2 ,minimum,
U)
This alternative parameterization of the Lognormal distribution is useful for modeling expert estimates of some continuous quantity with a long right tail, like time or cost to complete a task.
The LognormalAlt distribution appears in the standard Select Distribution palette. It also appears in the Expert selector window when one selects two percentiles {(P1, X1), (P2, X2)} and a minimum.
ModelRisk has two other distributions that can be used with this alternative parametisation: the LogLogisticAlt and the WeibullAlt. It is a good idea to compare all three distributions together to see which gives the most realistic interpretation of the input parameters.
VoseLognormalAlt generates values from this distribution or calculates a percentile.
VoseLognormalAltObject constructs a distribution object for this distribution. Professional and Industrial editions only.
VoseLognormalAltProb returns the probability density or cumulative distribution function for this distribution. Professional and Industrial editions only.
VoseLognormalAltProb10 returns the log10 of the probability density or cumulative distribution function. Professional and Industrial editions only.