Mean Bootstrap

This is a histogram of the data.
Click on Run to draw samples of the size specified.
You’ll see the sample against the data.
Specify the number of samples you wish to draw and the sample size then press 'Run'.
The tool will draw that many samples.
Each sample is shown in the upper histogram and its mean displayed in the “Sample Mean” box then the mean is dropped into the lower histogram.

If you wish to test a simple hypothesis for the mean, specify the null hypothesis value in the input box below. The lower histogram will be shifted so you can test the hypothesis.

Otherwise, leave the input box empty to not perform the test.

This is a histogram of the means of the samples we’ve drawn from the data in the upper histogram.

Notice several features:

• This histogram tends to be more bell-shaped and symmetric than the upper one.
• The means in this histogram are much less spread out than the data. You can see this by comparing the blue region in this histogram with the corresponding blue region in the upper one, since they cover the same values.

You can drag the flags that define the tails by clicking and dragging them.

Alternatively, you can use the keyboard. Make sure you have one of the tails in focus, you can do this by clicking the lower histogram or by navigating to it using th tab key. Once you've focused on the lower histogram, you control the left tail with the left and right arrow keys. On their own, the arrow keys move the left tail Three sample at a time. You can move 1% of the total samples at a time by holding the shift key with the left or right arrow keys. You can move 10% of the total samples at a time by holding Control and Shift at the same time as pressing the left or right key.