CEVAP:

1. An unknown population parameter is to be estimated.
2. A sample including n independent observations is selected randomly from the population and a particular function of the sample observations is used as an estimate of the parameter.
3. The sample observations are obtained from the independent random variables X1, X2, ... Xn. Thus, the statistic to be calculated is also a random variable. Therefore, the probability distribution of the statistic is called its sampling distribution.