theorem :: RANDOM_1:36

for Omega being non empty set
for r being Real
for Sigma being SigmaField of Omega
for P being Probability of Sigma
for X being Real-Valued-Random-Variable of Sigma st 0 < r & X is nonnegative & X is_integrable_on P holds
P . { t where t is Element of Omega : r <= X . t } <= (expect (X,P)) / r