8) If a testing device or other equipment is
used, show that: a. the type of device
used is reliable and / or accepted as dependable for such
use by an appropriate
body of scientific thought and
by studies, experiments and field
use; b. the method of operation of the device and the particular device
used are of an accepted type and in good working order; c. the operator of the device was competent to
use the device
by training and experience; and d. that the particular test was
correctly done.