The null hypothesis attempts to show that no variation exists between variables, or that a single variable is no different than zero. It is presumed to be true until statistical evidence nullifies it for an alternative hypothesis.
Bias introduced to a sample when a large fraction of those sampled fails to respond.
Numerical methods used to determine whether research data support a hypothesis or whether results were due to chance
Estimation of an unknown quantity between two known quantities historical data, or drawing conclusions about missing information from the available information.