Uncertainty Assessment of Hydrological Frequency Analysis Using Bootstrap Method

Table 1

Estimation of design value 𝑥_𝑝.

Nonexceedance; Probability 𝑝 (%)	Bootstrap method					Curve-fitting method
	Sampling distribution of 𝑥𝑝	Ex𝑝 (mm)	CI90%	CIL	SD	Point estimation (mm)
99.9	𝑋99.9%∼𝑁(1748,89)	1748	[1601,1895]	294	89	1704
99	𝑋99%∼𝑁(1517,59)	1517	[1420,1615]	195	59	1497
98	𝑋98%∼𝑁(1441,51)	1441	[1357,1525]	168	51	1427
95	𝑋95%∼𝑁(1333,41)	1333	[1265,1401]	136	41	1328

Notation: Ex_𝑝 is the expectation of the sampling distribution of 𝑥_𝑝, and SD is its standard deviation; CI_90% is the 90% confidence intervals, and CIL_90% is its length.