Survey Methods

• Central Limit Theorem

Illustrates the central limit theorem by allowing the user to increase the number of samples in increments of 100, 1000, or 10000.

• Chi-Square Sampling Distribution Generator

This page generates a graph of the Chi-Square distribution and displays the associated probabilities. Users enter the degrees of freedom (between 1 and 20, inclusive) upon opening the page.

• Standard Error Calculator of Sample Means

This page calculates the standard error of a sampling distribution of sample means when users input the mean and standard deviation of the population and the sample size.

• What is a Survey?

A series of pamphlets place online by the American Statistical Association, Survey Research Methods Section. Each pamphlet deals with a different aspect of survey research and how it is done.
• Analysis Tool: Binomial Distribution

This page will generate a graphic and numerical display of the properties of a binomial sampling distribution, for any values of p and q, and for values of n between 1 and 40, inclusive.

• Survey Design

This site takes the user through the steps and decisions necessary when designing a survey. Pros and cons for each method are outlined and other issues in survey design are presented.
• Confidence Intervals for Means Applet

This applet simulates finding confidence intervals for the mean of a normal random variable. A sample of size 20 is generated from a standard normal random variable. The blue marks represent the sample data. The sample mean X and sample standard deviation s are found and used to calculate the confidence interval. The black intervals are the confidence intervals which include the true mean 0, and the red intervals are those which exclude 0. This applet needs to be resized for optimal viewing.