# Sampling & Survey Issues

• ### data Collection: PollingReport.com

An independent, nonpartisan resource on trends in American public opinion. Gives examples of recent polls, margins of error, questions asked, and sample sizes.
• ### Racing Game with One Die

This applet allows the user to simulate a race where the results are based on the roll of a die. For each outcome of the die, the user chooses which player moves forward. Then that car moves forward the given number of spaces. Users can experiment with the race by determining which player will win more often based on the rules that they specify.

• ### Sexual Activity

This page provides survey data on the sexual activity of male and female subjects and discusses choosing appropriate statistics to describe the data as well as reporting bias. It also links to a Chance article about the same study.
• ### Distribution Calculator Lines

The program DistCalc calculates probabilities and critical values for the most important distributions. The purpose of this program is to show the concept of critical values and the replacement of printed distribution tables. The Distribution Calculator offers calculations for the normal distribution, the t distribution, the chi-square distribution, and the F distribution.

• ### Dataset: Mortality Data

These are MIT's epidemiology database pages. Mortality data for the United States from 1890-1997, Japan from 1951-1994, and Massachusetts, New York, Pennsylvania, Illinois, California, Texas and Florida dating back to the late 1950's are provided.
• ### Video: Against All Odds: 17. Samples and Surveys

This free online video program "shows how to improve the accuracy of a survey by using stratified random sampling and how to avoid sampling errors such as bias. While surveys are becoming increasingly important tools in shaping public policy, a 1936 Gallup poll provides a striking illustration of the perils of undercoverage."
• ### **Normal Approximation to the Binomial Distribution

This demonstration allows you to view the binomial distribution and the normal approximation to it as a function of the probability of a success on a given trial and the number of trials. It can be used to compute binomial probabilities and normal approximations of those probabilities.
• ### Sampling Bias and The California Recall

This lesson deals with the statistics of political polls and ideas like sampling, bias, graphing, and measures of location. As quoted on the site, "Upon completing this lesson, students will be able to identify and differentiate between types of political samples, as well as select and use statistical and visual representations to describe a list of data. Furthermore, students will be able to identify sources of bias in samples and find ways of reducing and eliminating sampling bias." A link to a related worksheet is included.
• ### Average, Standard Deviation and Relative Standard Deviation

This pdf file gives definitions for average, standard deviation, and relative standard deviation, and works through a short problem as an example.
• ### ** Hypothesis Test for a Mean

This Java applet tutorial prompts the user to input the components of a hypothesis test for the mean. Hints are provided whenever the user enters an incorrect value. Once the steps are completed and the user has chosen the correct conclusion for accepting or rejecting the null hypothesis, a statement summarizing the conclusion is displayed. The applet is supported by an explanation of the steps in hypothesis testing and a description of one-tailed and two-tailed tests.