Bootstrap Statistics (Resampling with Replacement)

Bootstrapping is a technique for measuring sample statistics from a relatively small set of data elements. By randomly resampling with replacement from the array of data elements, the software is able to generate a distribution that approximates the Normal Distribution from which parametric statistics like mean, standard deviation, skewness, and kurtosis can be estimated.

In the iPhone version, there must be at least 6 data items (0 is a number, n/a is not) and resampling will create 10,000 sets, each of whose size will be one-third the number of data items.

Along with an increase in the range of numbers that can be input, the iPad version adds two user-defined options. One lets the user select the number of times samples will be taken with replacement between 2 and 5 times. Another allows varying the number of resamples in a computation between 10,000 and 250,000 times.

Also, the iPad version displays a graph of the histogram derived from the frequency of resamples overlaid by the familiar bell-shaped curve of the Normal Distribution. In addition, you may add, retrieve, reorder, or delete data sets. Also, data and results may be emailed, sent via text messaging, or printed.


changes in version 6.0
  • Changes necessitated by iOS 13 & 14
  • Removed links to Facebook and Twitter
  • Various GUI changes and enhancements
  • Some code simplification
changes in version 5.5
  • GUI changes
  • Bug fixes
changes in version 5.4
  • In iPhone version, replaced stepper button with two buttons that will increment or decrement the data entry figures continuously if pressed and held down or one number at a time if pressed and released immediately
  • In iPad version, arrow buttons increment or decrement their respective sliders with single touches
  • Sharing of report uses Apple's standard set of links to media such as SMS text messages and email
  • Modified Facebook sharing syntax
  • Various GUI modifications
  • Redesigned app icon
changes in version 5.0
  • iPad version now adds email, text message, and print capability. A PDF report at a resolution of 72 dpi is available for sharing
  • Also, in iPad version there are now 10 more data points for data entry
  • Streamlined and improved source code
  • Because new data fields have been added, previously saved data sets will be replaced by the default data sets
changes in version 4.0
  • Rewritten and redesigned for iOS 7
  • Added warning to prevent inadvertent resetting of all data in both iPhone and iPad versions
  • GUI enhancements

revised: June 26, 2021