In a clinical trial I have 1000 patients with disease A. Their mean treatment cost is 1000$ per patient with a 95% confidence interval of [900;1100] for example. The whole population of country X is 10 Mio. Prevalence of disease A in country X is 5%, with a 95% confidence interval of [4.5%,5.5%].
How do I calculate the total costs including the 95% interval for country X?
I'd also like to see a Bayesian approach if appropriate.