3. The following code will read in data on the vaccination percentages in different countries load("VaccPerc.Rdata") x=VaccPerc hist(x) Now assume that each data point * ~Beta (a ) ) comes from a beta distribution with shape parameters a and b . If your priors are a ~ Gamma ( shape= 2 ,scale= 3) b exp(rate= 1) Use MCMC to draw samples from the posterior distribution of a and b . Run your MCMC sampler long enough to obtain an effective sample size of at least 500. Report the posterior mean and a 95% CI on both estimated parameters