It was unclear how the sample were selected.
Regardless of how the sample is selected, the observations are realizations of random variables due to the model assumptions.
In the present study, we have performed a systematic analysis of network characteristics such as average degree, betweenness, clustering coefficient, and geodesic length, and have shown how these characteristics depend not only on the sample size but also on how the sample is selected.
This means that important considerations such as who commissioned polls and for what purpose; how questions were framed; or how the sample was selected are overlooked.
All sample households with an address were sent a primary approach letter explaining the purpose of the survey, how the sample was selected, who would be asked to do the survey, and about how long it would take.
Five related to the quality of the reporting of a study's aims, context, rationale, methods and findings (e.g. was there an adequate description of the sample used and the methods for how the sample was selected and recruited?).
The sample was selected intentionally.
For example, the author calculated an "approximation of the experimental error" using the correlation coefficient of two samples, but I found no explanation for how these two samples were selected.
For a functional description of the wood communities, six samples were selected for shotgun metagenome sequencing.
Thin sections (7 cm × 5.5 cm), from undisturbed soil samples, were selected in order to show how the methodology works and its potential application.
