General Rules
Given an event, A, what equation gives you the probability that event A will NOT occur?
What is ....
P(A') = 1 - P(A)
or
P(A')+P(A)=1
A coin is tossed 3 times. What is the probability that it lands on heads exactly one time?
What is...
0.375
Events that do not impact each other's probability.
What is...
independent
What is ...
P(rolling three 4s) = P(4)*P(4)*P(4) = P(4)^3
or (1/6)*(1/6)*(1/6)= (1/6)^3
At NNHS, the probability that a student has 2nd lunch is .57. The probability that the student has 2nd lunch and is in Math Class is .32. What is the probability of a having 2nd lunch given that they are in Math Class?
.56
Given two independent events, A and B, what is the probability that event A and B occurs.
What is...
P(A and B) = P(A) * P(B)
Armando is a high school baseball player. He gets a hit 70% of the time. That means his average is 0.70. What is the probability that he gets his first successful hit on his third swing?
What is ...
0.3*0.3*0.7= 0.063
two events that cannot occur simultaneously
What is....
mutually exclusive or disjoint
The rule for the probability of pulling a red or queen from a standard deck of cards.
What is...
P(Red or Queen)= P(red)+P(queen) - P(red and queen)
There are 15 girls and 8 boys in Mrs. Meaney's 7th period. There is a 50% chance that a student will leave the classroom during 7th period. What is the probability of a student leaving the classroom given that they are a boy?
1/2
Given two mutually exclusive events, A and B, what is the probability that event A or event B occurs?
What is ...
P(A or B)= P(A) + P(B)
The two equations used to determine independence between 2 events.
What is...
P(A|B)=P(A)
or
P(B|A)=P(B)
two events that cannot occur together, but one must happen
What is...
complementary
The rule for finding the probability of a female given that they are an AP stats student.
The chance of a teacher at Newton North attending trivia night is .03. The chance of them attending trivia night and leaving early is .005. What is the probability of the teacher leaving early given that they attended trivia night?
.17
Given two events, A and B, what is the probability that event A and B occurs.
What is...
P(A and B) = P(A) * P(B|A)
90% of the people who have a particular disease will have a positive result on a given diagnostic test (90% accuracy). If 5% of a certain population has the disease, what percent of that population would test positive for the disease?
What is ...
14% or 0.14
events that do not impact each other's probability
what is ...
dependent
The probability of not drawing a red ace or a club from a standard deck of card
What is ...
1- P(drawing a red ace) - P(drawing a club)There is a 13/52 chance of a person drawing a spade from a normal deck of cards. What is the probability of a person drawing another spade from the deck given that the first card was not put back into the deck (without replacement)?
12/52
Given two events, A and B, what is the probability that event A or event B occurs?
What is ...
P(A or B)= P(A) + P(B) - P(A and B)
or
P(A or B)= P(A) + P(B) - P(A)*P(B|A)
Two events are this if they share no outcomes in common
What is ...
disjoint or mutually exclusive
contains all of the possible outcomes
what is...
sample space
The rule for finding the probability of 2 or more people from a group of 5 having the same birthday
1- P(none have the same birthday)
P(none have the same birthday)= (365/365) *(364/365) * (363/365) * (362/365) * (361/365)
What is the probability that you will roll a three on your second roll of a dice, given that you rolled a 3 on your first roll?
1/6