Consider conducting a stratified random sampling to estimate the mean $($using sample mean estimator, ratio mean estimator and regression mean estimator$)$ of a population of your choice in Uganda. In the process of executing the survey and making the estimates, write short notes on the following.

a$)$ What particular problems arise in establishing a sampling frame, such as a map or list of units from which to select the samples?

b$)$ How is the samples selection actually carried out?

c$)$ What problems might arise in observing $/$interacting with units selected?

d$)$ Suppose the auxiliary information relevant for computing the ratio or regression estimators are available, explain how you would use these estimators?

e$)$ Explain how would you execute proportional and optimum allocation of these sample size.