Probability - Sample space
- Definition of probability
- Sample space of an experiment
- Events and outcomes
- Methods of representing a sample space
- Types of events: certain, impossible, simple, compound
- Example 1: Tossing a coin
- Example 2: Rolling a die
- Example 3: Selecting a card from a deck
- Probability of an event
- Law of total probability
Probability - Mutually exclusive events
- Mutually exclusive events definition
- Intersection of events
- Union of events
- Disjoint events
- Example 1: Drawing a red or black card
- Example 2: Tossing a fair coin
- Example 3: Rolling a die and getting an odd or even number
- Calculation of probabilities for mutually exclusive events
- Addition law of probability for mutually exclusive events
- Notation for mutually exclusive events
Probability - Independent events
- Independent events definition
- Joint probability
- Conditional probability
- Multiplication law of probability for independent events
- Example 1: Tossing two fair coins
- Example 2: Drawing two cards from a deck without replacement
- Example 3: Rolling two dice and getting a sum of 7
- Calculation of probabilities for independent events
- Notation for independent events
Probability - Dependent events
- Dependent events definition
- Conditional probability with dependent events
- Example 1: Drawing two cards from a deck with replacement
- Example 2: Selecting balls from an urn with replacement
- Example 3: Drawing two marbles from a bag without replacement
- Calculation of probabilities for dependent events
- Multiplication law of probability for dependent events
Probability - Complementary events
- Complementary events definition
- Complement of an event
- Properties of complementary events
- Example 1: Tossing a fair coin
- Example 2: Drawing a card from a deck
- Example 3: Rolling a die
- Calculation of probabilities for complementary events
- Notation for complements
Probability - Addition law of probability
- Addition law of probability definition
- Union of events
- Example 1: Tossing a fair coin
- Example 2: Rolling a die
- Example 3: Drawing a card from a deck
- Calculation of probabilities using addition law
- Notation for addition law of probability
Probability - Multiplication law of probability
- Multiplication law of probability definition
- Intersection of events
- Example 1: Tossing two fair coins
- Example 2: Drawing two cards from a deck with replacement
- Example 3: Selecting balls from an urn
- Calculation of probabilities using multiplication law
- Notation for multiplication law of probability
Probability - Conditional probability
- Conditional probability definition
- Example 1: Drawing a card of a particular suit
- Example 2: Selecting balls from an urn
- Example 3: Rolling dice and getting a sum divisible by 3
- Calculation of conditional probabilities
- Notation for conditional probability
Probability - Bayes’ theorem
- Bayes’ theorem definition
- Theorem statement
- Example 1: Cancer screening test
- Example 2: Selecting a card from a deck
- Example 3: Tossing three fair coins
- Calculation of probabilities using Bayes’ theorem
- Applications of Bayes’ theorem
- Probability - Sample space
- Definition of probability
- Sample space of an experiment
- Events and outcomes
- Methods of representing a sample space
- Types of events: certain, impossible, simple, compound
- Example 1: Tossing a coin
- Sample space: {H, T}
- Events: {H}, {T}, {H, T}
- Probability of getting heads: P(H) = 1/2
- Probability of getting tails: P(T) = 1/2
- Example 2: Rolling a die
- Sample space: {1, 2, 3, 4, 5, 6}
- Events: {1}, {2}, {3}, {4}, {5}, {6}
- Probability of getting a particular number, e.g., P(3) = 1/6
- Example 3: Selecting a card from a deck
- Sample space: 52 cards in a standard deck
- Events: drawing a certain card, drawing a red card, drawing a face card
- Calculating probabilities for different events using the size of the sample space and the number of favorable outcomes
- Probability of an event
- Probability of an event A: P(A)
- Calculating probability using the formula: P(A) = favorable outcomes / total outcomes
- Properties of probability: 0 <= P(A) <= 1
- Probability of an impossible event: P(A) = 0
- Probability of a certain event: P(A) = 1
- Law of total probability
- Law of total probability formula: P(A) = P(A ∩ B1) + P(A ∩ B2) + … + P(A ∩ Bn)
- Applying the law of total probability to calculate the probability of an event A when the sample space is partitioned into mutually exclusive events B1, B2, …, Bn
- Probability - Mutually exclusive events
- Mutually exclusive events definition
- Intersection of events
- Union of events
- Disjoint events
- Example 1: Drawing a red or black card
- Example 2: Tossing a fair coin
- Example 3: Rolling a die and getting an odd or even number
- Calculating probabilities for mutually exclusive events using the addition law of probability
- P(A ∪ B) = P(A) + P(B) when A and B are mutually exclusive events
- Probability - Independent events
- Independent events definition
- Joint probability
- Conditional probability
- Multiplication law of probability for independent events
- Example 1: Tossing two fair coins
- Example 2: Drawing two cards from a deck without replacement
- Example 3: Rolling two dice and getting a sum of 7
- Calculating probabilities for independent events using the multiplication law of probability
- P(A ∩ B) = P(A) * P(B) when A and B are independent events
- Types of events: certain, impossible, simple, compound
- Certain events: Events that will always occur, with a probability of 1.
- Impossible events: Events that will never occur, with a probability of 0.
- Simple events: Events that consist of a single outcome. For example, getting a specific number when rolling a die.
- Compound events: Events that consist of more than one outcome. For example, getting an even number when rolling a die.
- Example 1: Tossing a fair coin
- Sample space: {H, T}
- Possible events: {H}, {T}, {H, T}
- Certain event: Getting either heads or tails (H or T)
- Impossible event: Getting neither heads nor tails (not H and not T)
- Example 2: Rolling a die
- Sample space: {1, 2, 3, 4, 5, 6}
- Possible events: {1}, {2}, {3}, {4}, {5}, {6}
- Certain event: Getting any number from 1 to 6
- Impossible event: Getting a number less than 1 or greater than 6
- Example 3: Selecting a card from a deck
- Sample space: 52 cards in a standard deck
- Possible events: Drawing a specific card, drawing a red card, drawing a face card
- Certain event: Drawing any card from the deck
- Impossible event: Drawing a card that is not in the deck
- Calculation of probabilities for different events
- Probability of an event A: P(A)
- Calculating probability using the formula: P(A) = favorable outcomes / total outcomes
- For example, the probability of drawing a face card from a deck is P(face card) = 12 / 52 = 3 / 13
- Law of total probability
- Law of total probability formula: P(A) = P(A ∩ B1) + P(A ∩ B2) + … + P(A ∩ Bn)
- Applying the law of total probability to calculate the probability of an event A when the sample space is partitioned into mutually exclusive events B1, B2, …, Bn
- For example, if we partition the sample space of rolling a fair die into the events of getting an even or odd number, the probability of getting a 3 can be calculated using P(3) = P(3 and even) + P(3 and odd)
- Example 1: Tossing two fair coins
- Sample space: {HH, HT, TH, TT}
- Possible events: {HH}, {HT}, {TH}, {TT}
- Certain event: Getting any combination of heads and tails
- Impossible event: Getting a combination that is not in the sample space
- Example 2: Drawing two cards from a deck with replacement
- Sample space: 52 cards in a standard deck
- Possible events: Drawing a specific pair of cards, drawing two red cards, drawing two spades
- Certain event: Drawing any two cards from the deck
- Impossible event: Drawing two cards that are not in the deck
- Example 3: Selecting balls from an urn
- Sample space: Number of balls in the urn
- Possible events: Drawing a specific ball, drawing a red ball, drawing an even-numbered ball
- Certain event: Drawing any ball from the urn
- Impossible event: Drawing a ball that is not in the urn
- Calculation of probabilities for dependent events
- Probabilities for dependent events can be calculated using the multiplication law of probability
- P(A ∩ B) = P(A) * P(B|A)
- For example, if we want to calculate the probability of drawing two red cards without replacement, we first determine the probability of drawing a red card on the first draw, followed by the probability of drawing a red card on the second draw given that a red card was already drawn on the first draw.