Overview for Probability Theory I | MATH 511, Study notes of Mathematics

Material Type: Notes; Professor: Tebbs; Class: PROBABILITY; Subject: Mathematics; University: University of South Carolina - Columbia; Term: Unknown 1989;

Typology: Study notes

Pre 2010

Uploaded on 10/01/2009

koofers-user-sgl
koofers-user-sgl 🇺🇸

7 documents

1 / 2

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
STAT/MATH 511 OVERVIEW STAT 512, J. TEBBS
Here is a summary of some of the main ideas from the prerequisite STAT/MATH 511:
Probability. WMS stands for Wackerly, Mendenhall, and Schaeffer (text).
Chapter 1 (WMS): Overview of basic statistics. We skipped this chapter (STAT 110).
Chapter 2 (WMS): Basic probability theory, set notation, Kolmorogov axioms, com-
plement rule, tools for counting (e.g., combinations, permutations, etc.), conditional
probability, Law of Total Probability, Bayes Rule.
Chapter 3 (WMS): Discrete random variables (positive probability is assigned to spe-
cific points), probability mass functions (pmf), means and variances of discrete random
variables, moment generating functions, Bernoulli trials. Important discrete models:
1. Discrete uniform. Equal probability assigned to each support point.
2. Binomial, b(n, p) (Bernoulli, n= 1). Number of successes out of nBernoulli trials.
3. Geometric, geom(p). Number of Bernoulli trials until 1st success.
4. Negative binomial, nib(r, p). Number of Bernoulli trials until the rth success; gen-
eralisation of the geometric.
5. Hypergeometric, hyper(N, n, r ). Number of Class 1 objects selected from r. Finite
population version of the binomial.
6. Poisson, Poisson(λ). Records counts in a Poisson process over time or space.
Chapter 4 (WMS): Continuous random variables (positive probability is assigned to
intervals; not specific points), probability density functions (pdf), cumulative distribution
functions (cdf), means and variances of continuous random variables, moment generating
functions, Chebyshev. Important continuous models:
1. Uniform, U(θ1, θ2). Pdf is constant over the interval from θ1to θ2.
2. Normal, N(µ, σ2). Most widely used probability model. E(Y) = µand V(Y) = σ2.
Symmetric, unimodal, “bell-shaped.”
PAGE 1
pf2

Partial preview of the text

Download Overview for Probability Theory I | MATH 511 and more Study notes Mathematics in PDF only on Docsity!

STAT/MATH 511 OVERVIEW STAT 512, J. TEBBS

Here is a summary of some of the main ideas from the prerequisite STAT/MATH 511: Probability. WMS stands for Wackerly, Mendenhall, and Schaeffer (text).

Chapter 1 (WMS): Overview of basic statistics. We skipped this chapter (STAT 110).

Chapter 2 (WMS): Basic probability theory, set notation, Kolmorogov axioms, com- plement rule, tools for counting (e.g., combinations, permutations, etc.), conditional probability, Law of Total Probability, Bayes Rule.

Chapter 3 (WMS): Discrete random variables (positive probability is assigned to spe- cific points), probability mass functions (pmf), means and variances of discrete random variables, moment generating functions, Bernoulli trials. Important discrete models:

  1. Discrete uniform. Equal probability assigned to each support point.
  2. Binomial, b(n, p) (Bernoulli, n = 1). Number of successes out of n Bernoulli trials.
  3. Geometric, geom(p). Number of Bernoulli trials until 1st success.
  4. Negative binomial, nib(r, p). Number of Bernoulli trials until the rth success; gen- eralisation of the geometric.
  5. Hypergeometric, hyper(N, n, r). Number of Class 1 objects selected from r. Finite population version of the binomial.
  6. Poisson, Poisson(λ). Records counts in a Poisson process over time or space.

Chapter 4 (WMS): Continuous random variables (positive probability is assigned to intervals; not specific points), probability density functions (pdf), cumulative distribution functions (cdf), means and variances of continuous random variables, moment generating functions, Chebyshev. Important continuous models:

  1. Uniform, U(θ 1 , θ 2 ). Pdf is constant over the interval from θ 1 to θ 2.
  2. Normal, N (μ, σ^2 ). Most widely used probability model. E(Y ) = μ and V (Y ) = σ^2. Symmetric, unimodal, “bell-shaped.” PAGE 1

STAT/MATH 511 OVERVIEW STAT 512, J. TEBBS

  1. Gamma, gamma(α, β). Popular model for random variables with positive support. Shape parameter, α; scale parameter, β. Skewed right, in general.
  2. Exponential, exponential(β). A gamma distribution with α = 1. Exponential- decay shaped pdf.
  3. χ^2 , χ^2 (ν). A gamma distribution with α = ν/2 and β = 2. Degrees of freedom parameter, ν. Popular model in applied statistics.
  4. Beta, beta(α, β). Support over (0, 1). Very flexible model for proportions.
  5. Other “named” distributions: Cauchy, Weibull, log-normal, Pareto, etc.

Chapter 5 (WMS): Random vectors, multivariate distributions (particular attention paid to bivariate distributions), joint pmfs and pdfs, marginal distributions, conditional distributions, independence, multivariate expectations, covariance/correlation, multino- mial distribution, bivariate normal, conditional expectations, iterated rules for mean and variance.

Going forward: It will be helpful to know all of the named discrete/continuous dis- tributions (that we discussed in STAT/MATH 511), their pmfs/pdfs, means, variances, and moment generating functions. Recall that the cumulative distribution function for a random variable Y is given by

FY (y) = P (Y ≤ y).

Useful integral shortcuts: For α > 0 and β > 0, recall that ∫ (^) ∞ 0 yα−^1 e−y/β^ dy = Γ(α)βα

and (^) ∫ (^1)

0 yα−^1 (1 − y)β−^1 dy = Γ(Γ(αα)Γ( + ββ)).

These facts follow from the properties of gamma and beta pdfs, respectively. Recall that the gamma function Γ(s) satisfies Γ(s) = (s − 1)Γ(s − 1), for s > 1.

PAGE 2