Chapter 6: Probability Flashcards
What is probability?
A measure of how likely an event is to happen.
Probabilities can be expressed as fractions, decimals, or percentages.
What is an outcome?
A possible result of an experiment or trial.
Example: when rolling a dice, the outcomes are 1, 2, 3, 4, 5, and 6.
What is an event?
A specific thing that has a probability of happening.
Example: rolling an even number.
How is probability calculated?
P(event) = Number of successful outcomes / Total number of outcomes.
What do the probabilities of all outcomes add up to?
1.
What is expected frequency?
The number of times you expect an event to happen based on probability.
Example: P(Heads on a coin) = ½, so in 10 flips, expect heads 5 times.
What is experimental probability?
Probability based on the results of previous trials.
What is the formula for estimated probability?
Estimated Probability = Number of trials with successful outcomes / Total number of trials.
What is another name for estimated probability?
Relative Frequency.
What does increasing the number of trials do to the accuracy of probability?
Makes it more accurate.
What is risk in probability?
The probability of a negative event occurring.
What are the two types of risk?
- Absolute Risk
- Relative Risk
Define absolute risk.
How likely an event is to happen, represented by relative frequency.
Define relative risk.
How much more likely an event is to happen for one group compared to another group.
What is a sample space?
A list of all possible outcomes.
Example: When rolling a fair six-sided dice, the sample space is 1, 2, 3, 4, 5, and 6.
What is a sample space diagram?
A table used to represent the outcomes of two events.
What is a Venn diagram used for?
To represent all the outcomes of two or three events happening.
What must the sum of all probabilities in a Venn diagram equal?
1.
What are mutually exclusive events?
Events that cannot happen at the same time.
Example: Getting heads and tails on a coin flip.
What is the formula for mutually exclusive events?
P(A or B) = P(A) + P(B).
What are exhaustive events?
Events that contain all possible outcomes.
What is the Addition Law in probability?
Used for events that are not mutually exclusive: P(A or B) = P(A) + P(B) - P(A and B).
What is the Multiplication Law for independent events?
P(A and B) = P(A) × P(B).
What are independent events?
Unconnected events where the outcome of one does not affect the other.
Example: Flipping a coin and rolling a dice.
What does a tree diagram represent?
Each branch represents an outcome, with probabilities adding up to 1.
What is conditional probability?
When one event affects the chances of another event happening.
What is the notation for conditional probability?
P(B | A) = P(A and B) / P(B).
How can you identify conditional probability in a question?
Look for phrases like ‘given that’ or ‘if’.
