MTBF is an abbreviation for "mean time between failures" and is
often used by companies to try and improve. A person can calculate
the MTBF by dividing the sum of operational hours by the number of
failures.
View page
MTBF = 1/failure rate R(t) = e (-t/MTBF)
http://www.vicorpower.com/documents/quality/Rel_MTBF.pdf