# Simulation

• ### What Makes the Standard Deviation Larger or Smaller? (Star Library)

The activity is designed to help students develop a better intuitive understanding of what is meant by variability in statistics. Emphasis is placed on the standard deviation as a measure of variability. As they learn about the standard deviation, many students focus on the variability of bar heights in a histogram when asked to compare the variability of two distributions. For these students, variability refers to the "variation" in bar heights. Other students may focus only on the range of values, or the number of bars in a histogram, and conclude that two distributions are identical in variability even when it is clearly not the case. This activity can help students discover that the standard deviation is a measure of the density of values about the mean of a distribution and to become more aware of how clusters, gaps, and extreme values affect the standard deviation. Key words: Variability, standard deviation

• ### Which Paper Towel is More Absorbent? (Star Library)

This group activity focuses on conducting an experiment to determine which of two brands of paper towels are more absorbent by measuring the amount of water absorbed. A two-sample t-test can be used to analyze the data, or simple graphics and descriptive statistics can be used as an exploratory analysis. Students are asked to think about design issues, and to write a short report stating their results and conclusions, along with an evaluation of the experimental design. Key words: Two-sample t-test

• ### What is the Shelf Life? (Star Library)

The Food and Drug Administration requires pharmaceutical companies to establish a shelf life for all new drug products through a stability analysis. This is done to ensure the quality of the drug taken by an individual is within established levels. The purpose of this out-of-class project or in-class example is to determine the shelf life of a new drug. This is done through using simple linear regression models and correctly interpreting confidence and prediction intervals. An Excel spreadsheet and SAS program are given to help perform the analysis. Key words: prediction interval, confidence interval, stability

• ### 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.

• ### The Gambler's Ruin Problem

This applet allows you to experience the fate of a gambler by simulating the whole gambling session in a matter of seconds. The applet plots the successive rises and falls of the capital during the whole duration of the game. It also displays the maximum and minimum values attained by the capital during the session and allows you to get precise information (by clicking at a point of the histogram) of the amount of capital after that particular bet.
• ### Let's Make a Deal

This page has links to an explanation of the applet and to the applet itself. It is a simulation of the T.V. game show. There are three doors to choose from and after making a choice, one of the other doors is revealed. The player can choose to pick the other unopened door or stay with their original choice. Afterwards the statistics of previous contestants are shown. (Note: the applet statistics are inaccurate)
• ### Introduction to Cryptography: Games and Programs

This is a collection of applets including Let's Make A Deal, Let's Make a Deal II, Monkey Words, Entropy, Vigenere, Rectangular Transposition, and Monoalphabetic Substitution.
• ### Let's Make a Deal II

This applet doesn't have more explanation than - Let's Make a Deal II- An applet to demo at the UCLA conference. It has statistics for a number of tries at a time with choices for whether or not the host knows what is behind the door and whether or not the contestant switches doors after primary choice.
• ### Shannon's Experiment to Calculate the Entropy of English

The following applet allows you to simulate the Shannon experiment, an experiment aimed at determining the entropy of an English letter (the amount of information in bits that we obtain on the average when we learn one letter of English). The simulation will calculate the amount of entropy for you when you are finished guessing the letters.
• ### Breaking The Vigenere Encryption System

This applet is programmed to illustrate the code-breaking process using the Vigenere encryption as the code. The Vigenere encryption is broken by comparing histograms of various frequencies until the correct guess is obtained. A wrong guess for the period p leads to relatively flat histograms. The code breaker in this case repeats the analysis with a new trial period.