This function calculates a random draw from the full conditional posterior distribution for s_ij in the Li algorithm, given the observed values yijs, the parameter pi, the lambda_i value, and the truncation level S.
postSij(yijs, pii, lambdai, S)
A random draw from the posterior distribution of s_ij.
Vector of observed values for s_ij.
Probability parameter pi.
Value of lambda_i.
Truncation level.