Page 74 - Math SL HB Sem 3

Statistics and probabitiry

IND EVENTS

Two events A and B are independent:

Ifthe probability ofevent B occuring is not influenced * A occur;j
l) P(lnB):P(A) xP@) "urnt
rhen P(AUB):P(A)+ p6sy-p(A)x p(B) ) ?ca\s')= fcn)

2) P(48): p(A) and p(Bll) p(B) +) f ts1a,) tc|)
=
=

Example:
Two fair dice are rolled. Find the probability that two even numbers wifl show up.

f)xample:
A factory runs two machines, A and B- Machine A operates for g0zo of the time whire
machine B operates for 600% of the time and at reast one machine operatcs for 92yo of the
time. Do these machine operate independently?

'lL