Lexis Trials

$n$ sets of $s$ trials each, with the probability of success $p$ constant in each set.

$$\mathop{\rm var}\nolimits \left({x\over n}\right)= spq+s(s-1){\sigma_p}^2,$$

where ${\sigma_p}^2$ is the Variance of $p_i$.

See also Bernoulli Trial, Lexis Ratio