Page 35 - Math SL HB Sem 3

>ComplementolA,A'
The compliment of A, /', means NOT I
NotethatAvA'=U
I
I so, P(.4) + P(A') = 1
ll T r This gives us
t
I I P(A',) L-P(A)
U -

) Mutually exclusive events
P(A^B)-O
t
A a
t lt From the Venn diagram or the probability formula:
I t I P(A u B) : P(A) + P(B) - P(A B)
t I We have ^
t I
U P(Au B) -P(A) +P(B)

) Exhaustive events

lf set.4 and set B include all the possible outcomes
A D
: (i.e. AU B = U), event A and B are said to be exhaustive.
t t I That is,
t T
:: t I P(Au B) r
-
U

\ Example:

Consider events .4 and B, where 14
P(A')=-;P(B)=-

27
and P(A u B\ =-
35
a) Write down P(/).
b) Find P(,4 n B).
c) Are events / and B mutually exclusive?

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