  Measured values of arm asymmetry parameter x = (theta> - theta<)/(theta> +
theta<) of a double have appreciable random errors due to errors in positions
of radio peaks & of the optically identified galaxy or quasar. These broaden
the monotonic decreasing x-distribution g(x). In addition, finite resolution &
blending of complex structure leads to errors in recognizing peaks leading to
systematic overestimate of x. Thus both random & systematic errors broaden
g(x), & consequently broaden the distribution p(v) of derived hotspot
separation speed v, & shift its peak to larger v, since p(v) = -v.g'(v).
  Keywords: active galaxies - double radio sources - bilateral symmetry - arm
asymmetry
