# DCOM Volume I Appendix J

From Ministry of Water DCOM Manual

# APPENDIX J: Basic Statistics Used in Estimation Of Design Of Flood Events

Generally, the basic statistics such as mean, standard deviation, variation coefficient and skewness coefficient gives basic information of data.

Distribution
We obtained the daily maximum rainfall by return period through methods such as two- parameter log-normal, three-parameter log-normal, Gumbel, type Ⅲ log-person distributions as expressed here below.
**Two parameter log-normal distribution**
ln X_{T}=Y_{T}=M_{Y} + K_{T}.ð_{T}
Where ln X_{T} : Probable Rainfall

Y_{T}: ln X_{T}