Answer:
when the population is small
when the sample contains proportions of items/events/people that are different from those of the population
Step-by-step explanation:
The sampling method is resorted to only when
i) population is large
ii) Surveying entire population is time consuming
iii) surveying the entire population is expensive
iv) when the sample contains only items/events/people that reflect the population
Otherwise, when population is very small we can survey the whole population instead of sample.
Similarly when sample contains proportions of items/events/people that are different from those of the population, the survey will not be effective if sampling is adopted
Hence we have choosing a sample from a population least likely to be appropriate whenever
the population is small
and or the sample contains proportions of items/events/people that are different from those of the population
