  Approximations for the mean performance indices for the M/G/c queue rely on
the approximate computation of the probability that an arriving request has to
wait for service and of the minimum of residual service times if all servers
are found busy. Using numerical examples, we investigate properties of these
two quantities. In particular, we show that the minimum of residual service
times depends on higher order properties, beyond the first two moments, of the
service time distribution. Improved knowledge of the properties of the two
quantities studied in this paper provides insight into avenues for improving
the accuracy of approximations for the M/G/c queue.
