So-called accidental sampling. Please see the link.
The related web sites give a good idea of the types of non-random sampling. These include snowball, convenience, quota, self-selection, diversity, expert, and others. Non-randon sampling is usually done because it is less expensive, easier, and quicker than random sampling.
Convenience judgment sampling involves selecting participants based on their easy accessibility and proximity to the researcher, often leading to biased results due to a lack of randomness. In contrast, random sampling aims to give every individual in the population an equal chance of being selected, thereby enhancing the representativeness of the sample and reducing bias. While convenience sampling is quicker and less expensive, random sampling is more rigorous and reliable for generalizing findings to a broader population.
Advantage -- Less effort, cost, work Disadvantage -- Less accuracy, information, difficulty of establishing true 'randomness" in some samplings.
Suitable sampling techniques other than stratified sampling include simple random sampling, where each member of the population has an equal chance of being selected; systematic sampling, which involves selecting every nth individual from a list; and cluster sampling, where the population is divided into clusters, and entire clusters are randomly selected. Convenience sampling, though less rigorous, involves selecting individuals who are easily accessible. Each method has its own advantages and limitations, depending on the research goals and population characteristics.
You get a non-random sample and any analysis based on the assumption of randomly distributed variables is no longer valid. In particular, your estimates of any variables are likely to be biased and your error estimates (standard errors or sample variances) will be incorrect. Any inferences based on statistical tests will be less reliable and may be wrong.
because it is the simplest sampling technique which requires less time and cost.
There are many such methods: cluster sampling, stratified random sampling, simple random sampling.Their usefulness depends on the circumstances.
The related web sites give a good idea of the types of non-random sampling. These include snowball, convenience, quota, self-selection, diversity, expert, and others. Non-randon sampling is usually done because it is less expensive, easier, and quicker than random sampling.
Advantage -- Less effort, cost, work Disadvantage -- Less accuracy, information, difficulty of establishing true 'randomness" in some samplings.
Suitable sampling techniques other than stratified sampling include simple random sampling, where each member of the population has an equal chance of being selected; systematic sampling, which involves selecting every nth individual from a list; and cluster sampling, where the population is divided into clusters, and entire clusters are randomly selected. Convenience sampling, though less rigorous, involves selecting individuals who are easily accessible. Each method has its own advantages and limitations, depending on the research goals and population characteristics.
You get a non-random sample and any analysis based on the assumption of randomly distributed variables is no longer valid. In particular, your estimates of any variables are likely to be biased and your error estimates (standard errors or sample variances) will be incorrect. Any inferences based on statistical tests will be less reliable and may be wrong.
e.g. you wanted to conduct a test on teenagers, if you wanted to test an entire population you would have to test every teenager in the world. BY using random sampling or stratisfied random sampling you can get fair results which represents the entire population and takes far less time.
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.
Not less than double the highest frequency component of the signal you're sampling.
Less time and less cost for a sample
in flat top sampling the electronic circuit required for sampling are less complicated as compared to the one used in natural sampling, at demodulation of the sample it is very difficult to maintain the natural waveform of the natural sampling so flat top sampling can easily be demodulated.
Not less than 10V