We exploit the exact solution for the ground stare of the one-dimensional s
pinless quantum gas of fermions with mu /x(ij)(2) interaction. The availabl
e analytical pair densities for mu = -1/4, 0, and 2 allow us to analyze par
ticle-number fluctuations. They are suppressed by repulsive interaction (mu
>0), enhanced by attraction (mu <0), and measure the kind and strength of
correlation. Other recently proposed purely quantum-kinematical measures of
the correlation strength arise from the small-separation behavior of the p
air density or-for fermions-from the nonidempotency of the momentum distrib
ution and its large-momenta behavior. They are compared with each other and
with reference-free, short-range correlation-measuring ratios of the kinet
ic and potential energies.