apple-0.1.0.0: math/t.apple

λxs.λys.
{
  sum ⇐ [(+)/x];
  𝜇 ⇐ λxs.λn. sum xs%n;
  𝜎 ⇐ λxs.λn. {𝜇 ⟜ 𝜇 xs n; sum ([(x-𝜇)^2]'xs)%(n-1)};
  xsn ⟜ ℝ(:xs); ysn ⟜ ℝ(:ys);
  𝜈 ⟜ xsn+ysn-2;
  sₚ ← √(((xsn-1)*(𝜎 xs xsn)+(ysn-1)*(𝜎 ys ysn))%𝜈);
  t ← (𝜇 xs xsn-𝜇 ys ysn)%(sₚ*√(1%(xsn+ysn)));
  t
}