probability Flashcards
P(event)=
required/total outcomes
if a coin is tossed, P(H)=
1/2
if a coin is tossed, P(T)=
1/2
if a die is thrown , P(1)=
1/6
if a die is thrown, P(5)=
1/6
total probability is always equal to
1
probability always lies between
0 and 1
P(x)=0, x is
impossible
P(x)=1, x will
certainly occur
at least minimum
at least maximum
and/ both means
multiply
or/either means
add
sample space
P(x)= curly bracket ,,_ curly bracket
tree diagram
the total of each branch is always 1
don’t forget to label
intersection
U
union
intersection means
multipy
union means
+ and - with the intersection
possibility space diagram is used for
2 fair die
use factorial when
number of outcomes are random
P(ABC)=
3!
P(AAB)=
3!/2!
P(AA BBB)=
5!/2!*3!
P(AAA)
3!/3!
use combination for
random and without replacement events
mutually exclusive events
2 events cannot take place simultaneously
mutually exclusive events conditions
independent events
if either events A and B can occur without being affected by the other, then the 2 events are said to be independent
independent events conditions
P(A, given B) or
P(AIB)
P(AIB)=
conditional probability type
if 2 events are independent
they cannot be mutually exclusive and vice versa
straight
multiply
one particular boy
so keep him fixed
