An analysis of the influence of the length of the record in the reliability of mean values of precipitation was made for the Caracus-Cagigal Station in Venezuela. Ten series of values were obtained for 10, 15, 20, 25, 30, and 35-year periods, extracted for sliding intervals for the overall record of 75 years. The reliability of mean values computer from Figure 3 was quite low for 10, 15, and 20- year periods. The long term record means had higher reliability, increasing with the number of years in the records, but the differences are not important in terms of accuracy. Precipitation values for .2, .10, .20, .30, .40, .50, .60, .70, .80 .90, and .95 equal or less probability levels were computed based on an incomplete gamma distribution for 126 stations distributed throughout Venezuela. Computer programs were used to process the data.
Ramirez, Luis E., "Development of a Procedure for Determining Spacial and Time Variations of Precipitation in Venezuela" (1971). Reports. Paper 145.