The normal probability paper for frequency analysis of rainfall data is constructed with the help of a commercial computer, digital computer, software; HARVARD Graphics version 2. 12. The annual maximum daily total rainfall data of 21 years (from 1970 to 1990) for the station, Tarnab, Peshawar has been collected and analyzed as a case study. A graphical comparison of the original data and data generated using three different theoretical probability distributions i. e. Log-Pearson Type III distribution, Lognormal distribution and Gumbel distribution has been made.