Intuitive examples are to roll a pair of dice, flip a fair coin, or draw a ball from a well-mixed urn. One feature of random selection is that it is free of bias, i.e., characteristics of the researcher do not systematically influence the selection process, and characteristics of the elements do not systematically influence the process. Then, using a table of random numbers, choose 10 numbers. The 10 whose number corresponds to the 10 selected using the table of random numbers would be in your sample. Generalization should only be made to the population from which a representative sample was selected.
People often make claims about their results being generalizable to other populations.
Treat these skeptically. Sampling error refers to the to difference between the true mean and the sample mean, summed over all possible sample means. Usually you don t know this and it has to be estimated. As sample size increases, sampling error decreases. SRS Each population member has an equal probability of selection.