The degree to which a sample might differ from the population.

The process of selecting some part of a population to observe and to estimate something of interest about the whole population (ex: the abundance of a rare or endangered species in the population might be estimated by the pattern of detections from a sample of sites taken in the study region). These methods assume that each member of the population has a known non-zero probability of being selected (probability sampling methods). They include simple random sampling, systematic sampling, and stratified sampling. Sampling error, which is the degree to which a sample might differ from the population, could be calculated and results are reported plus or minus the sampling error.

The levels or sizes at which particular ecological entities or processes are considered. One distinction that is often made is between local, regional and biogeographic scales.

Facts obtained by making observations and measurements.

Educated guesses that attempt to explain scientific observations or scientific laws. It is the first step in the scientific method.

The way scientists gather and evaluate information; it involves observations, hypothesis formulation and testing.

Description of what scientists find happening in nature repeatedly in the same way without known exceptions. See scientific theories.

Well-tested and widely accepted explanations of data and laws.

A statistical procedure that when applied to a set of observations results in a probability value (p-value) relative to some hypothesis. Examples: Student’s t test, Wilcoxon’s test.

It considers that each member of the population has an equal and known chance of being selected by random sampling. This is mainly true for very large populations.