20.4.21  Inverse distribution functions

The icdf command finds the inverse cumulative distribution function for a probability distribution.

• cdf takes one or more mandatory arguments and one optional argument.
  • distd, the name of the function that finds the distribution’s density function.
  • params, any parameters that would normally be passed to distd.
  • x, a number.
• icdf(distd,params) returns an expression for the inverse cumulative distribution function for distd with parameters params.
• icdf(distd,params,x) returns the value of the inverse cumulative distribution function at x.

Example