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.
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.
This applet shows a scatterplot of height versus foot length. Users can add or delete points and then guess the regression line by clicking "Your Line" and moving the blue regression line. By clicking "Regression Line" users can see the actual regression line. The applet also shows the correlation and R-square for the data as well as the residuals and squared residuals for the guessed regression line and the actual regression line.
This module provides an activity were students will attempt to explain how each of the following variables is related to child poverty within the United States: Race, Age, Family Type, Family Size, and Immigrant Status.
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.
This page contains links to 5 review sheets with formulas, properties, definitions and rules for basic descriptive and inferential statistics and probability concepts. The review pages are in pdf format. Key Words: Hypothesis Testing, ANOVA, Descriptive Statistics, Regression, Correlation, Nonparametric Tests, Probability Distributions, Counting, Central Limit Theorem.
This site contains numerous resources for learning statistics. Under "Free Statistical Software", the user will find many, many links to free statistical software packages. Also available on the site are links to statistical textbooks, tutorials, applets, calculators, data sources, and more.
