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Probability Theory Final Quick Course (Knowledge Points and Examples)

2024-07-12

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Examination Scope

one:

  • Event relation operation
  • nature
  • Total probability formula, Bayesian formula
  • Classical Archetype

two:

  • Discrete distribution law
  • Continuous density function properties -> Solve three problems (find the unknown coefficients, find the probability, find the density function)
  • Distribution function -> solve three problems
  • Common distributions (the ones in the last lesson)

three:

  • Seven discrete (continuous) type questions: (distribution law (coefficient of determination)), probability, marginal distribution (density), independence, conditional distribution (density), function distribution, covariance (correlation coefficient)

Four:

  • Mathematical expectation, variance (calculation, common distribution, analysis)
  • Chebyshev's inequality
  • Two-dimensional - correlation and independence, covariance of two variables

five:

  • Central Limit Theorem

first lesson

1.1 No-replacement questions (classical probability model)

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1.2 Questions with Replacement

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1.3 Questions that require drawing

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1.4 Total Probability Formula

The probability of two independent events A and B occurring at the same time is P(AB) = P(A) * P(B)

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1.5 Bayesian formula

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1.6 Event Probability (Relational Operation/Conditional Probability)

addition:

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Subtraction:

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Multiplication and division:

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Independent events do not affect each other.

Second lesson

2.1 Given one of the distribution function Fx(x) and the density function fx(x), find the other

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2.2 Given one of Fx(x) and fx(x), find P

The equal sign in P has no effect here. The presence or absence of the x subscript in F or f has no effect on itself.

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2.3 Fx(x) or fx(x) contains unknowns. Find the unknowns.

Several formulas for standardization.

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2.4 Finding the distribution law

The distribution sequence is the distribution law.

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Problems like rolling dice are sequencing problems (A).

2.5 Given a distribution sequence containing unknown numbers, find the unknown numbers

Given the following distribution, find the value of k.

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Lesson Three

3.1 Given the distribution of X, find the distribution of Y

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The following can also be written:

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Fourth lesson

4.1 Find the probability of uniform distribution

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4.2 Find the probability of Poisson distribution

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4.3 Find the probability of binomial distribution

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4.4 Find the probability of exponential distribution

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4.5 Normal distribution, find the probability

Standard normal distribution, N(0, 1).

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fifth lesson

5.1 Given a two-dimensional discrete distribution law, what is it?

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5.2 Given a two-dimensional discrete distribution law, determine independence

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5.3 Given F(x, y), find f(x, y)

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5.4 Distribution Function F(x) and Probability Density f(x) of a Continuous Two-Dimensional Variable

5.4.1 Finding the probability density f(x) and probability

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5.4.2 Finding the Undetermined Coefficients and Distribution Function F(x)

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What if there are three unknown terms? Use segmentation to find out the continuity.

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Lesson Six

6.1 Finding the Marginal Distribution Function

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6.2 Finding the Marginal Density Function

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6.3 Determining the independence of continuous two-dimensional variables

fx(x) and fy(y) have already been found in the previous problem type.

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6.4 Two-dimensional discrete random distributions (joint, marginal, conditional distributions, and independence)

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6.5 Two-dimensional continuous random distributions (joint, marginal, conditional density, and independence)

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By norm, the probability of the rectangular area is 1.

The discrete type is to find the distribution law.

Lesson Seven

7.1 Finding the Discrete Expectation E(x)

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7.2 Finding the expectation E(x) of a continuous form

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7.3 Given Y = g(x), find E(y)

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7.4 Finding the Variance D(x)

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7.5 Performing complex operations based on the properties of E(x) and D(x)

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7.6 Comprehensive Problems on E(X), D(X) and Various Distributions

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Lesson Eight

8.1 Covariance Cov, density coefficient Pxy, variance D and related questions

Discrete:

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Continuous type:

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If P(rou) is not equal to 0, then X and Y are correlated.

8.2 Using Chebyshev's inequality to find probability

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8.3 Multiple independent and identically distributed numbers, what is the probability of the sum?

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Lesson 9

9.1 Finding the Expectation of a Discrete Form

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9.2 Finding the Expectation of a Continuous Form

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9.3 Given Y=g(x), find E(Y)

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9.4 Finding the Variance D(x)

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9.5 Complex operations based on the properties of E(x) and D(x)

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9.6 Comprehensive Problems on E(x), D(x) and Various Distributions

0-1 distribution: E(x) = p; D(x) = p(1 - p)

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The binomial distribution is also a Bernoulli distribution (independent, n repeated trials, each time there are only two results, A and not A).

Lesson 10

Central Limit Theorem

n variables, independent, identically distributed

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After normalization, we get the standard normal distribution:
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