# Chapter 3: Estimators and Distributions

Online Statistical Calculators and Tables
This page contains links to online calculators that compute either critical values or p-values for commonly used distribution functions.

W.I.S.E. Tutorial: Sampling Distributions
This online tutorial, provided by the Web Institute for Statistical Education at Claremont College, provides a nice review of the normal distribution, the distribution of sample means, the central limit theorem, and the use of z-scores. A java applet effectively illustrate these concepts.

The Central Limit Theorem (Berrie's Statistical Page)
This site provides a very nice discussion of the central limit theorem. A quicktime movie clip illustrates how quickly a binomial distribution tends toward a bell-shaped normal distribution as the number of drawings increase.

Interactive graph of the normal distribution (Berrie's Statistical Page)
This java applet provides a graph of a normal distribution function. The user is able to change the mean and the standard deviation and see how the distribution shifts.

Normal distribution (Berrie's Statistical Page)
This page contains a description of the normal distribution function. Quicktime movies illustrate the effect of changing the mean and the variance of the distribution.

Galton's Board and the Normal Distribution (Berrie's Statistical Page)
Galton's board is a simple mechanical device that illustrates how the sum of outcomes from a binomial distribution can be approximated by a normal density function. The Java applet on this page provides a graphical depiction of the functioning of this device.

The Normal Distribution (by Balasubramanian Narasimhan)
This page contains a description of the normal density function and a Java Applet that allows the user to view the effect of changes in the mean and variance of a normal distribution on the position and shape of the density function. Two other applets illustrate the use of the normal density function to construct confidence intervals.

Probability and Quantile Applets (by Balasubramanian Narasimhan)
The first applet on this page allows the user to find areas within any region under the normal density curve. The second applet can be used to find the z-score corresponding to any given probability value for a normal cumulative density function.

Student's T-distribution (by Balasubramanian Narasimhan)
This page provides a Java applet that illustrates the relationship between a t-distribution and a standard normal distribution for alternative degrees of freedom. You can use this applet to see how quickly the t-distribution converges to a standard normal distribution as the size of a sample rises. On this page you can also learn how a brewing company was responsible for providing us with the use of t-statistics.

Sampling Distribution Simulation (Rice Virtual Lab in Statistics)
This Java Applet illustrates the relationship between a sampling distribution and the underlying population distribution.

Statistics: The Study of Stability in Variation, by Jan de Leeuw
This online statistical text contains a solid discussion of statistics. While it becomes rather advanced fairly quickly, the introductory section provides a good discussion of many of the basic statistical concepts discussed in this chapter.

HyperStat Online (David M. Lane)
This is an online hyperlinked statistics text that discusses most of the statistical concepts that you will need for this course.

Statistics UCLA - Case Studies
This site, provided by the University of California at Los Angeles, contains a wonderful collection of case studies illustrating real-world applications of basic statistical analysis. Each of these case studies is set up as a problem for students to solve using basic statistical techniques.
John Kane - kane@oswego.edu
Department of Economics, SUNY-Oswego, Oswego, NY 13126