 
              subjects 300   controls 25
     log(L)=-125.3   slope=6.238+-1.173   nat.resp.=.106+-.021
     heterogeneity=.57   g=.136
     LD10=.663   limits: .460 to .801
     LD50=1.065   limits: .911 to 1.210
     LD90=1.709   limits: 1.467 to 2.244
