# Graphical Displays

• ### **Dotplot Summaries Applet

This applet generates dotplots for different data sets and allows users to guess the location of various measures of center and spread. Clicking "Resample" produces a dotplot of random data generated by the applet. A dotplot of user-input data can be generated by clicking "Edit Data" and typing or copy and pasting the data in the textbox. To guess the mean, median, standard deviation, and interquartile range (IQR) users check the "Guess Mean/Median", "Guess Deviation", or "Guess IQR" box and slide the relevant marker along the horizontal axis. When "Guess Deviation" is selected, users can also select "Show Percentages" to display the percentage of data points within the user's current guess for standard deviation. Clicking "Show Actual" displays the actual position of the selected measure on the dotplot. Clicking on an individual data point shows its value. Users can edit the data under "Edit Data" or by clicking and dragging the data points on the graph.
• ### Statistics at Square One: Exact Probability Test

This section of an online textbook discusses calculating the exact probability using observed sets of frequencies, constructing frequency tables, and computing p-values. Exercises and answers are provided.
• ### Dataset Example: Move Over, Roger Maris: Breaking Baseball's Most Famous Record

The dataset presented in this article referes to game-by-game information for Mark McGwire and Sammy Sosa during summer of 1998. This data can be used to demonstrate graphical displays, categorical data analysis, analysis of variance, logistic regression, and smoothing methods for Poisson and binomial data.
• ### Dataset Example: A Dataset that is 44% Outliers

This article describes a dataset of days in office of US Presidents with outliers that are not mistakes or unusually high or low observations. The data illustrate that outliers need not be errors but could be particularly interesting cases and that data displays may differ in their ability to reveal interesting data structure. Key Words: Inliers; Interpretation in context.
• ### Data Collection: Data Matters with Excel: Estimating Population Variance

This activity uses Microsoft Excel to estimate the population variance of grouped data two ways: the variance within a group and the variance between groups. This activity accompanies Section 7.3 of Data Matters.
• ### Statistics and Probability Concepts

This is a collection of activities as Java applets that can be used to explore probability and statistics. Each activity is supplemented with background information, activity instructions, and a curriculum for the activity.
• ### Random Babies Activity

This worksheet activity teaches random sampling and theoretical probabilities by simulating the effects of randomly assigning newborn babies to their mothers. Students will perform trials and keep track of results, then use the information to deduce properties of random sampling. The relation website is an applet that simulates the process automatically.
• ### Data Collection:US Census Bureau: Census 2000 Datasets

Users can select from detailed tables and geographical comparison tables to generate data from the 2000 Census.
• ### Joke: Walking into a bar

an old "walks into a bar" joke with a statistics twist.

• ### A Tutorial on Mathematical Modeling

This general, introductory tutorial on mathematical modeling (in pdf format) is intended to provide an introduction to the correct analysis of data. It addresses, in an elementary way, those ideas that are important to the effort of distinguishing information from error. This distinction constitutes the central theme of the material described herein. Both deterministic modeling (univariate regression) as well as the (stochastic) modeling of random variables are considered, with emphasis on the latter. No attempt is made to cover every topic of relevance. Instead, attention is focussed on elucidating and illustrating core concepts as they apply to empirical data.