Let me refer back to a couple of seemingly contradictory posts from just
before the outbreak of insanity in this thread.
On arriving at the lock-up, the officer afforded him an opportunity
to "blow again" to see if it was any lower. Surprise, it was higher!
Not a huge surprise. What is more surprising is that even if it were
lower than the first reading it still could have hurt his
defence!
in most cases, when you are offered the opportunity to "re-test"
you are digging a hole for yourself and strengtaning the case for the
state.
This contradicts what arcniz said, namely, "If you ever are in a
situation where you must involuntarily give a sample, politely demand
that they run two blood samples." In fact, each of the two strategies
is correct for the persons to which it is directed.
If you are under the limit, as arcniz assumes, then you want as many
tests as possible. If you are over the limit, as SAM 2 seems to suppose,
then you want as few tests as possible. Let me give an example. Its
conclusions have been reached using statistical information that was
typical of well-conducted BAC tests fifteen years ago. I don't know if
there have been any changes to the tests since then and if there have
been I do not have current data. Nevertheless, the statistical principles
behind the conclusions would remain valid regardless of any changes that
may have taken place. Suppose the limit BAC is 0.04 and you test at 0.046
on your first sample. The correct statistical decision is to accept the
hypothesis that your true BAC is under the limit. However, if you
are given two more tests and your two additional test results decrease
to 0.044 and 0.042 then the correct statistical decision is to reject
the hypothesis that your BAC is under the limit.