# One Numerical Variable

• ### Galton's Board or Quincunx

This applet demonstrates the Binomial distribution by simulating Galton's Board, dropping balls through a triangular array of nails. When a ball hits a nail, it has a 50 percent chance of falling to the left or the right. Because Galton's Board consists of a series of experiments, the piles under the board are the sum of n random variables, where n is the number of rows of nails on the board.
• ### Song: You've Got Your Models

Song includes vocabulary from fitting models, including outliers and assumptions. May be sung to tune of "You've Got Your Models" (The Fortunes). Musical accompaniment realization and vocals are by Joshua Lintz from University of Texas at El Paso.
• ### Song: Bayesians in the Night

Song playfully celebrates Bayesian inference and includes various vocabulary such as coherence, prior, and exchangeable. May be sung to the tune of "Strangers in the Night" (Kaenpfert/Singleton/Snyder). Musical accompaniment realization and vocals are by Joshua Lintz from University of Texas at El Paso.
• ### Song: Bayes! (You're the One for Me!)

Song celebrates Bayesian inference, includes verbal form of Bayes theorem. The lyrics were written by David Blackwell, University of California at Berkeley. May be sung to the tune of "Who (Stole My Heart Away)?" (Jerome Kern).  The audio was produced by Nicolas Acedo with vocals by Abeni Merriweather, both students in the Commercial Music Program at The University of Texas at El Paso.

• ### Race and Changing Household Structure

The textbook for this course discusses cross-cultural variations in household structure, as well as changes across time in household structure in the United States. The purpose of this exercise is to examine variations in household structure in the United States according to race and historical period. By the end of the exercise students should have a better appreciation of the fact that household structure in the U.S. is very fluid and that changes over time in household structure have not progressed uniformly for all race groups.
• ### Cohabitation

This module is designed to illustrate the effects of selection bias on the observed relationship between premarital cohabitation and later divorce. It also serves as a review of key methodological concepts introduced in the first part of the course.
• ### Histogram Applet

This applet generates a histogram for two provided datasets, or by clicking "Edit Data", users can input their own data. Users can also manipulate the axes and bin width.
• ### **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.
• ### Normal Probability Calculator

This applet allows users to calculate probabilities from a normal distribution. First, set the mean and standard deviation and click "Scale to Fit". Check one of the boxes next to the inequality signs and enter a value for x; the applet will calculate the z-score and cumulative probability (shown in dark blue for top value and pink for the bottom). By clicking both boxes, users can see the probability between two values (in pink) or outside two values (in blue). Click the inequality sign to change the direction of the cumulative probability.
• ### Mean

This resource defines and explains the arithmetic mean using an example on employee salaries.