This app is based on CUSUM, a sequential analysis technique firstly developed in 1940s.
The main function of this app is to draw the CUSUM curve for a selected skill. In this app, the users can create a skill by themselves and input the result (i.e. success or failure) at each time they finishing the skill practice. Then, the app will calculate the CUSUM value and show the CUSUM curve on the screen, in the meanwhile, the upper and lower boundaries will also be demonstrated to indicate whether the skill has been mastered or not. Besides, the parameters for computing the CUSUM value and boundaries are allowed to be set by the users.
In addition, this app requires the IOS 8.1.