Cauchy distribution

Click on the name of a distribution to access the corresponding entry of the Glossary

1

Click on a number to access the detailed Table of Contents of the Tutorial

 

 

 

CONTINUOUS DISTRIBUTIONS

 

 

 

 

 

 

Beta distribution

 

Tutorial

1

Relationship between the Beta and the Gamma functions.
   Moments of all orders. Mean. Variance.
   Transforming a Gamma and a Fisher's
F distributions
   into a Beta distribution.

Animation

Shapes of the Beta distribution as a function of the
    values of the parameters.

 

 

 

Cauchy distribution

 

Tutorial

1

Cauchy as the distribution of tg(q).
   Cauchy as the ratio of two standard normal r.v..
   Reciprocal of Cauchy is Cauchy.
   Sample mean of the Cauchy distribution is Cauchy.

Animation

The distribution of the sample mean does not depend on the     sample size, and is therefore identical to the "mother" distribution.

 

 

 

Chi-2 distribution

 

Tutorial

1

Basic properties of the Chi-square distribution.


2

Distribution of the sample variance.
   Loss a degree of freedom.
   Independence of the sample mean and the sample variance.

Animation

Shapes of the Chi-square distribution (number of degrees of     freedom adjustbale).
    Distribution of the true or estimated variance.

 

 

 

Exponential distribution

 

Tutorials

1

Basic properties of the exponential distribution.

2

Estimating the mean by the method of Maximum Likelihood.

3

Memoryless property of the exponential distribution.

4

Strong memoryless property of the exponential distribution.

5

Hazard rate function, failure rate.

6

Probability for a component to be the first one to fail.

7

Components in series, parallel, and on standby.

8

Expected lifetime of a system made of components in parallel.    Distributions of the spacings of the exponential distribution.

9

The "2// vs. 1" problem.

10

Random (geometric) sum of exponential variables.

11

Distributions of X1 and of X2 under the condition X1 < X2

Animations

Basic properties (mean, mode, standard deviation).

Estimating the mean by the method of Maximum Likelihood.

Memoryless property of the exponential distribution (probabilistic     viewpoint).

Memoryless property of the exponential distribution (distributional     viewpoint).
   Strong memoryless property of the exponential distribution.

Probability for a component to be the first one to fail.

Distribution of the min of several independent exponentials.

Expected lifetime of an "all parallel" system.
   Distribution of the spacings of the exponential distribution.

Distributions of X1 and of X2 under the condition X1 < X2

 

 

 

Fisher's F distribution

 

Tutorials

1

Probability density function of Fisher's F distribution.
   Mode.
   Mean, second order moment, variance.
   Distribution of the inverse of a Fisher random variable.

2

Mean and variance : second method.

 

See also :
       * Transforming a F distribution into a Beta distribution.

Animation

Shapes of Fisher's distribution depending of the values of the    numbers of degrees of freedom.

 

 

 

Gamma distribution

 

Tutorial

1

Recurrence relation of the Gamma function.
   Moments of all orders, variance.
   Moment generating function.
   Additivity. Sum of i.i.d. exponential r.v..
   Cumulative distribution function when α is an integer.
   Relationship with the Poisson distribution.

Animations

Shapes of the Gamma distribution as a function of the values of
   parameters α and
β.

The Gamma distribution as a sum of iid exponentials.

 

 

  

Normal distribution (Univariate)

 

Tutorials

1

Basic properties of the normal distribution

2

Estimation of the parameters of the normal distribution

3

Basic properties of normally distributed random variables

4

Normal distribution whose mean is itself a
   normally distributed r.v..

Animations

Sample mean is normally distributed

Estimation of the parameters of the normal distribution
   by the method of Maximum Likelihood

Normal distribution whose mean is itself a
   normally distributed r.v..

 

 

 

Normal distribution (Bivariate)

 

Tutorials

1

The standard bivariate normal distribution.
   The general bivariate normal distribution.

2

Uncorrelated yet not independent normal r.v..

Animations

Binormal distribution. Influence of :
        * The standard deviations,
        * and the correlation coefficient
    of the marginal distributions.

Two examples of uncorrelated yet not independent normal r.v..

 

 

 

Normal distribution (Multivariate)

 

Tutorials

1

Spherization of a multivariate normal distribution.
   Normalization coefficient.
   Mean vector.
   Covariance matrix.

2

Linear transform of a multinormal vector.
   Lack of correlation and independence of the marginals.    The marginal distributions of the multivariate normal    distribution are multinormal.
   Second demonstration.

3

The conditional distributions of the multivariate normal
   distribution are multinormal.
   The mean vector depends linearly on the conditioning
   variables.
   The covariance matrix does not depend on the
   conditioning variables.

Tutorials

4

Multivariate normal distribution and Regression.    
   Minimizing the predictions Mean Squared Error.    Maximizing the Multiple Correlation Coefficient.

5

Moment generating function of the
    multivariate normal distribution

Some immediate consequences of the Moment
   Generating Function :
      - Linear transform of a multinormal is multinormal.
      - Marginals are multinormal.
      - Uncorrelation implies independence.

A vector is multinormal iff all linear combinations of its    components are normal.

 

 

 

Order statistics

 

Tutorials

1

Distributions of the order statistics of the uniform distribution.
   Distributions of the order statistics of any distribution. 

2

Joint distribution of all order statistics.
   Joint distribution of two order statistics.

Animation

Distributions of the order statistics of the uniform distribution.

 

 

 

Record value

 

Tutorial

1

Distributions of the record values of the exponential distribution.
   Distributions of the record values of any distribution.
   Distributions of the record values of the uniform distribution.

Animation

Distributions of the record values of the exponential distribution.    Distributions of the record values of the uniform distribution.

 

 

 

Student's t distribution

 

Tutorials

1

Probability density function of Student's t distribution.
   Special cases : Cauchy, Normal (n infinite).
   Welch's approximation.

2

Variance of Student's t distribution :
       1) Direct approach by Wallis integrals.
       2) By LOTUS Theorem.

Animation

Student's t, normal and Cauchy distributions.
   Progressive histogram of Student's
t distribution.

 

 

 

Uniform distribution

 

Tutorials

1

Basic properties of the uniform distribution

2

Some applications of the uniform distribution.

3

Solutions to the four problems in the Glossary.

Animation

Four illustrated problems :
       * The "broken stick" distribution.
       * The "Shortest segment" problem.
       * The "Longest segment" problem.
       * The "Random choice" problem.

 

_______________________________________________________

MATHEMATICAL COMPLEMENTS

Jacobian

 

Tutorial

1

Bivariate transformations form first principles.

___________________________________________________________________________________

 

Downloading the Tutorials

On-line access to the Tutorials

Other Tutorials