Statistics Applets

Applet Sites

Descriptive Statistics

• Mean and Median.  A comparison between the mean and median is shown as you paint a histogram.

Normal Distributions

• Normal Probability Calculator.  Probabilities are calculated and drawn from a standard normal distribution between two given z-scores.
• Normal Approximation to the Binomial.  For certain values from a given binomial distribution, the binomial probability is compared to its normal approximation.
• Quincunx.  As balls fall through a field of pins they are collected at the bottom and form an approximate normal (or binomial where p = 0.5) distribution.

Other Distributions

Sampling Distributions and the Central Limit Theorem

• Sampling Distribution.  This is a very nice applet.  You are allowed to choose a parent population (normal, uniform, skewed or custom) from which to draw.  Different different types of sampling distribution can then be formed.
• Rolling Dice.  You control the number of dice and how many times they are rolled.  A relative frequency histogram of the results is shown.
• More Rolling Dice.  Similar to the previous dice applet except the vertical axis on the frequency histogram remains at a constant scale.

Regression and Correlation

• Influential Points.  A scatterplot with a regression line are given and you are allowed to add an additional point to see the affect it has on the regression line and the correlation.
• Errors and Residuals.  You plot your own points with the mouse and a regression line with vertical error lines is made.  A residual plot is also constructed.
• Estimating Regression and Correlation.  A scatterplot is given and 5 different correlation values are shown.  You are to estimate which correlation is correct and draw in the regression line.  The correct answers are then given.
• Guessing correlations.  Four scatterplots and four correlations are given.  You have to match them up.  You can repeat this process to see what percent you can get correct.
• Putting Points.  You are allowed to plot your own points and the regression equation and correlation are calculated throughout the process.

Confidence Intervals

• Confidence Intervals for a Population Mean.  Sampling is done from a population with a mean of 50 and a population of 10.  You can adjust the sample size and then 100 samples are then taken.  For each of these samples, 95% and 99% confidence intervals are computed and shown graphically.
• Confidence Interval for a Population Proportion.  For a specified sample size and population proportion, a large number of samples are taken and 95% confidence intervals are calculated.  The number of intervals that contain the population proportion is then reported.  You see how both the sample size and the population proportion affect this percentage.

Tests of Significance

• Tests of Proportions.  You can adjust the alpha level, the form of the hypotheses, or make p different from p0.  Sixty samples of size 30 are then drawn.  The applet graphically shows the samples where the null is rejected as well as those where the null is not rejected.
• Random Marble Grabber.  You can draw marbles out of a bag and a chi-square test statistic is calculated on the premise that the colors are evenly distributed.

• Probability

• Venn Diagram Applet.  A Venn diagram for two non-disjoint sets are shown within the universal set S.  You can choose from 16 different subsets of S.  Your subset will then be shaded on the Venn diagram.
• Let's Make a Deal.  The classic Monty Hall problem - should I stick or switch?
• Buffon's Needle Problem.   In playing this old classic you can estimate the value of pi.
• Pass the Pig.  A game in which "pigs" are tossed and a score is given as to how they land.