Introduction to Sampling Theory Population and Random Sample Population and Random Sample In statistical analysis,we still assume that the only ob- served data in Example 6.2 or Example 6.3 is one of many possible realizations from the random sample X". For some random samples,the order of the random vari- ables X1,...,Xn in the sample,together with their real- izations,may not be altered freely. An example is the time series random sample of Ex- amples 6.2,where the random variables X1,...,Xn are not jointly independent,and the behavior of X;may de- pend on the previous outcomes {X-1,X:-2,..}.Such a dynamic structure could not be preserved if one altered the order of random variables and their realizations. Introduction to Sampling Theory Introduction to Statistics and Econometrics April 16,2020 10/167Introduction to Sampling Theory Introduction to Sampling Theory Introduction to Statistics and Econometrics April 16, 2020 10/167 Population and Random Sample Population and Random Sample