Table : TABLE 12-2. Connections Among Distributions The z distribution is subsumed under the t distributions in certain specific circumstances, and both the z and t distributions are subsumed under the F distributions in certain specific circumstances.
When UsedLinks Among the Distributions
zOne sample; μ and σ are knownSubsumed under the t and F distributions
t(1) One sample; only μ is known
(2) Two samples		Same as z distribution if there is a sample size of ∞ (or a very large sample size)
FThree or more samples (but can be used with two samples)Square of z distribution if there are only two samples and a sample size of ∞ (or a very large sample size); square of t distribution if there are only two samples