definitions
what is the list of all possible outcomes
sample space
what is the probability of obtaining red
3/10
what is the rule?
pr (AuB) = pr(A) + pr(B) - pr(AnB)
pr(selecting a red card)
pr(selecting a red card) = 26/52 = 1/2
what is the collection of favourable outcomes?
events
what is the sample set
{red, red, red, blue, blue, blue, green, green, green, green}
sample space: {1,2,3,4,5,6,7,8,9,10}
A= even ,, B= numbers greater than 5
FIND pr (AuB)
pr (AuB) = pr(A) + pr(B) - pr(AnB)
pr (AuB) = pr(5/10) + pr(5/10) - pr(3/10)
pr (AuB) = 7/10
pr(selecting a red card or king)
pr(selecting a red card or king)= 29/52
element belongs to either a or b
union
what is the chance of obtaining a green?
4/10 = 2/5
FIND pr(AnB)
pr(AuB) = 0.8 , pr(A) = 0.3 , pr(B) = 0.6
pr(AuB)= pr(A) + pr(B) - pr(AnB)
0.8 = 0.3 + 0.6 - pr(AnB)
pr(AnB)= 0.9 - 0.8
pr(AnB) = 0.1
pr(club or queen)
the likelihood of an event occuring
probability
what is the probability of obtaining a red twice (with replacement)
9/100
FIND pr(AnB)' if pr(AuB)=0.7
1 - pr(AuB) = pr(AnB)'
1 - 0.7 = pr(AnB)'
pr(AnB)' = 0.3
pr(diamond or not king)
pr(diamond or not king) = 49/52
no elements in common
mutually exclusive
what is the probability of obtaining blue twice? (without replacement)
3/50
FIND pr(AnB)
pr (AuB)= 0.8, pr(A)= 0.5, pr(B)= 0.4
pr(AuB)= pr(A) + pr(B) - pr(AnB)
0.8 = 0.5 + 0.4 - pr(AnB)
pr(AnB) = 0.9 - 0.8
pr(AnB) = 0.1
pr (queen | black)
pr (queen | black) = pr(AnB)/ pr(B)
= 1/52/13/52
= 1/52 x 52/13
=1/13