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.
Quantifiable likelihood chance of the occurrence of an event expressed as odds, or a fraction of 1.
Necessitating a choice between mutually exclusive possibilities
A variable whose effect on the response variable cannot be separated from the effect of the explanatory variable on the response variable. Note: Usually confounded variables are lurking variables but only a few lurking variables are also confounded.