Chapter 5.2 Probability Sampling Methods Flashcards
Simple Random Sampling
each individual has equal chance for selection. each selection is independent of the others means that the choice of one individual doesnt affect choosing another individual. Use random process.
Simple Random Sampling: Sampling with replacement
This method requires that an individual selected for the sample be recorded as a sample member and then returned to the population before the next.
Simple Random Sampling: Sampling without replacement
Removes each selected individual from the population before the next selection. Guarantees that no individual appears more than once. However selection probability changes. In big samples theres almost no difference reducing one person.
Concerns about Simple Random Sampling
Sometimes exorted results can be reached like selecting too many men in random selection.
Systematic Sampling
Listing all the population then randomly picking a starting point on the list. The sample is then obtained by moving down the list selecting every nth name. The size of n dividing population size by the desired sample size. Principle of independence is violated because when we choose a starting point the next individual cannot be selected dependently. But it has a high degree of representetiveness.
Stratified Random Sampling
All subgroups must be identified first then select equal samples from them. Guarantees that each of the different subgroups will be represented in large group populations. %17 lik kısım %83 lük kısımla aynı derecede represent ediliyo.
Proportionate Stratified Random Sampling
identify subgroups, then all subgroups have to contain equally proportion to their size. But small proportions cannot be trusted at all time.
Cluster Sampling
Selecting groups not individuals. Select 10 classrooms each have 30 people in it instead of selecting 300 people one by one
Combined-Strategy Sampling
combining 2 or more strategies to select participants. generally increases representetiveness.