In reply to Mahadeb.

I think you mean "the area under the PDF curve." The PDF is the probability density function. The area under the PDF curve is given by the CDF, which is the cumulative distribution function. For the difference between these functions, see the article "Four essential functions for statistical programmers". If my explanation does not answer your question, you can ask questions like this at the SAS Statistical Procedures discussion forum.

The CDF function in SAS supports the lognormal, gamma, weibull, and beta distributions directly. Because the Johnson system is a transformation to normality, you can use the CDF for the normal distribution to compute the CDF for each distribution in the Johnson system.