week 4 機率論. basic probability concepts random trials sample spaces
TRANSCRIPT
Week 4 機率論
Basic Probability Concepts Random Trials
Sample Spaces
Events
1. Complementary Event
2. Joint Occurrence Event
3. Occurrence of One Event or Another
4. Mutually Exclusive Event
Probability Probability measure
P(E) denotes the probability that event E will occur
Probability Postulates (機率基本三公設)1.
2.
3.
Some Consequences of the Postulates
1. The sum of the probabilities of all basic outcomes in the sample spaces is 1
2. Every event has a probability value between 0 and 1
3. If E1 and E2 are two mutually exclusive events, then the probability of both occurring is zero.
Meaning of Probability 隨機試驗的特性 (1) 可重複執行的隨機試驗 (repeatable random expe
riment) 可以在完全相同的條件下反覆執行的隨機試驗
(2) 不可重複執行的隨機試驗 (unrepeatable random experiment) 無法在完全相同的條件下反覆執行的隨機試驗
Objective Interpretation Subjective Interpretation
Classical or a prior probability
Relative frequency or a posterior probability
Probability distribution
Univariate, Bivariate, and Multivariate probability distributions
Joint, Marginal, and Conditional Probability distributions
Relationships between variables Independent events
1.
2. 3.
Random variables A random variable is a variable whose
numerical value is determined by the outcome of a random trial.
1. Discrete random variables
2. Continuous random variables
Discrete random variables Probability distribution P(X=x) with each
distinct outcome x. Cumulative probability distribution
P(X<=x) Joint, Marginal, and Conditional probability
distributions
Expected value of random variable Variance of Random variable Standard Deviation of random variable Probability density function Cumulative probability function
Bernoulli Random Variable
Binomial Probability Function