Sampling techniques used in research

Lastly, the sample must not be so large that the study takes too long or is too expensive! This ensures that the statistical conclusions will be valid. Bias in sampling There are five important potential sources of bias that should be considered when selecting a sample, irrespective of the method used.

All the elements of the cluster are used for sampling. With cluster sampling, in contrast, the sample includes elements only from sampled clusters.

Non-probability sampling methods offer two potential advantages - convenience and cost. This may involve specifically targeting hard to reach groups. While sampling, these groups can be organized and then draw a sample from each group separately.

The fact that car buyers of every brand were equally represented in the sample is irrelevant to whether the sampling method was simple random sampling.

Sampling techniques ppt

Examples of stratums might be males and females, or managers and non-managers. The advantage of probability sampling is that sampling error can be calculated. Dialing numbers from a phone book for instance, may not be entirely random as the numbers, though random, would correspond to a localized region. Convenience Sampling When: During preliminary research efforts. In probability samples, each member of the population has a known non-zero probability of being selected. Cluster Sampling Multi stage Sampling Simple Random Sampling: Every element has an equal chance of getting selected to be the part sample. However, most surveys cannot survey the entire population. The fact that the sample was stratified should be taken into account at the analysis stage. Similarly, the fact that population consisted of buyers of different car brands is irrelevant. Each group is called a cluster. By dividing the number of people in the population by the number of people you want in your sample, you get a number we will call n. Stratified sampling.

Then, a blind-folded researcher selects n numbers. Each student has equal chance of getting selected.

non probability sampling techniques
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Survey Sampling Methods