It is when you specifically choose the people that you "sample", in order to collect data about them. (As opposed to picking numbers representing people out of a hat, etc... ). For example, if you wanted to collect some sort of data from every male currently living within the same postcode as yourself, that would be nonrandom.
"Non-random" varies a lot depending on what you're actually sampling. What would be "random" in one context can be "nonrandom" in another.
Chat with our AI personalities
They include: Simple random sampling, Systematic sampling, Stratified sampling, Quota sampling, and Cluster sampling.
Sampling and Non sampling errors
Random Sampling
simple random, stratified sampling, cluster sampling
Sampling error can be reduced by