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Advantages of cluster sampling include that it's inexpensive, fast, and simple. A disadvantage is that it is known to have a high sampling error.
I believe you are considering the sampling error as calculated from data. I will give you some examples: If you get the exactly same response from all participants in a survey, you will calculate zero sampling error. For example, if I ask 10 people if Obama Barack is the President of the US, I would probably get 10 "yes" responses. Now the answer was well known, so I would expect very few "no" response. If your measurements are not very sensitive or are recorded with a lack of precision, then there can be zero sampling error. For example, I take the body temperature of students at the college and consider any temperature from 97 to 99 degree F to be normal. I find all students in my sample have normal temperatures. So, zero sampling error can occur because a) sample is small, b) variation in response is either non-existent or very small. In theoretical calculations, where sample error is based on the probability distribution of the population, one can calculate for discrete variables, the probability that a sample error will be zero.
Sampling bias is a known or unknown selection of data to be examined in an audit. There should be no bias if the sample is random. Ex ... look at the first item in the file folder. or examine all files for purchases over $10,000, or examine no files for sales less than $500. Sampling error, is the incorrect selection of files for an audit. Ex ... a random number generator tells you to audit file 1547, but you select 1457. Sampling error is also used to describe the fact that auditing a sample will NOT create the exact same answer as auditing every single file or transaction.
In probability sampling,every item in the population has a known chance of being selected as a member.In non-probability sampling, the probability that any item in the population will be selected for a sample cannot be determined.
Sampling bias.