We analyze a sample of W + jet events collected with the Collider
Detector at Fermilab (CDF) in ppbar collisions at sqrt s = 1.8 TeV to study
ttbar production.  We employ a simple kinematical variable H, defined as the
scalar sum of the transverse energies of the lepton, neutrino, and jets.  For
events with a W boson and four or more jets, the shape of the H distribution
deviates by 3.8 standard deviations from that expected from known backgrounds
to ttbar production.  However, this distribution agrees well with a linear
combination of background and ttbar events, the agreement being best for a top
mass of 180 GeV/c^2.