PsiVary (base,min,max,[range_type],[dist_name],…)
PsiVary ( base, min, max, range_type, dist_name) can be used to specify a PsiTriangular (triang), PsiPert (pert), PsiUniform (uniform), PsiTriangGen (trianggen) or PsiNormalAlt (normal) distribution using a range defined by the min and max arguments which surround the base argument. There is no benefit to defining one of these functions using PsiVary. Note: This distribution was added for compliance with the @Risk Convert feature.
A distribution defined using PsiVary will be equivalent to the distribution defined in the "normal” way (i.e. using the Psi functions PsiTriangular, PsiPert, PsiUniform, PsiTriangGen or PsiNormalAlt) after a simulation has been completed. If a simulation has not yet been performed, PsiVary will return the value entered for the base argument while the PsiTriangular, PsiPert, PsiUniform, PsiTriangGen and PsiNormalAlt functions will return a random value from the respective distribution.
base: The value entered for base will be displayed before a simulation has been performed.
min: Enter the lower bound for triang, pert or uniform distributions. If entering a trigen or normal distribution, enter the 1st percentile value.
max: Enter the upper bound for triang, pert or uniform distributions. If entering a trigen or normal distribution, enter the 99th percentile value.
min <= base <= max
range_type: Optional: This is the method used to specify the range. Enter 0 (default) for -/+ percentage from the base argument, 1 for -/+ actual change from base and 2 for min and max as the actual lower and upper bounds.
dist_name: This argument must be one of the following: “triang” (default), “pert”, “uniform”, “trigen”, or “normal”.
Note: All arguments may be entered as a value, a cell reference or an expression.
Example: PsiVary(100, 95, 110, 2, “triang”) is equivalent to PsiTriangular(95, 100, 110)
Parameters: See PsiTriangular, PsiPert, PsiUniform, PsiTriangGen or PsiNormalAlt for definitions of each distribution’s parameters.