Table 5

CSU	Hayward
	Statistics	Department

Table 5. Gibbs Estimates of Prevalence From 10,000 Simulated Values After Burn-In
(Data: 5 positive tests among 215 units of blood)

Beta Prior
On Prevalence Simulated Values of p Gibbs Interval Estimate

Mean Median 2.5% 97.5%
(a) a = 2, b = 50 1.27% 1.11% (0.18%, 3.16%)

(b) a = 2, b = 20 2.51% 1.34% (0.21%, 3.74%)

(c) a = 1, b = 1 0.95% 0.75% (0.03%, 3.19%)

(d) a = 7, b = 5 4.42% 4.28% (1.99%, 7.61%)

Beta Prior On Prevalence	Simulated Values of p		Gibbs Interval Estimate
Beta Prior On Prevalence	Mean	Median	2.5%	97.5%
(a) a = 2, b = 50	1.27%	1.11%	(0.18%,	3.16%)
(b) a = 2, b = 20	2.51%	1.34%	(0.21%,	3.74%)
(c) a = 1, b = 1	0.95%	0.75%	(0.03%,	3.19%)
(d) a = 7, b = 5	4.42%	4.28%	(1.99%,	7.61%)