Do you need to know not only what the standard deviation, the spread and the range of a sequence of numbers are but also how to calculate them? If so then this App is for you. Not only will this App tell you the answer but it will also tell you how you can work it out for yourself using the information you have provided. Great for helping children trying to understand these concepts and for reminding yourself about them.

Just select the field at the top of the screen and a keypad will be shown. You type in the numbers in the sequence separating them using the space key (the empty key at the bottom left). When you have added all the numbers press the OK button. The keypad disappears and the answers are presented below in the table. On the iPhone there is another button at the top that leads to a page that explains how each of the averages was calculated. On the iPad the table to the right has the explanations.

The App calculates the Range, the lower quartile value, the upper quartile value, the interquartile range, and the standard deviation. It also explains how to calculate each of these values and in the case of the standard deviation shows you to different methods for calculating it.