Bootstrap Confidence Intervals

This applet estimates the confidence interval for a mean.

How to use the applet

  1. Choose a sample size, eqn, from the drop down box. Choose a sample size between 2 and 15.
  2. Enter a level, eqn, into the cell. Note, the cells in this applet act like a spreadsheet application; to change an entry, click on it, delete the current value, type a new one, and then press enter.
  3. Click "Generate New Data." A sample of size eqn will be displayed below the button in the row labeled "Data," and the sample mean, eqn, is automatically calculated and displayed below the data.
  4. You may edit the data in the row labeled "Data." Remember that these cells behave like a spreadsheet application, so press enter after you have edited a cell. The sample mean, eqn, is updated after you edit a cell and press enter.
  5. Choose a bootstrap sample size of eqn or eqn, and click "Generate Bootstrap Samples."
  6. A histogram of the means of the bootstrap samples is plotted. To view the bootstrap samples and their means, click "View Bootstrap Samples," and a new window will pop up.
  7. Below the plot, the confidence intervals are computed by two methods. They are Method I: eqn and Method II: eqn. The plot is shaded to highlight the confidence interval computed via Method I.

The applet

No Java Plug-in support for applet, see http://java.sun.com/products/plugin/