Frequently asked questions about Power on X:
Why was Power on X developed?
Power on X was developed to meet a need for a statistical power calculator that would run native on Mac OS X as all current calculators only ran in Classic.
What is the minimum system configuration I will need?
A Mac that is running Mac OS X 10.2 or greater. In general, if your machine meets the requirements to run Mac OS X, and is running 10.2 or greater, it should be able to run Power on X.
What sort of power calculations can Power on X perform?
At present Power on X will perform power calculations based on one and two-tailed t-Tests of means or correlations. Calculations can be a priori (performed on data derived from a pilot or previous studies) or post hoc where the data has already been derived.
How 'accurate / reliable' are the results generated by Power on X?
Tests of the algorithms used to calculate power values or sample sizes have demonstrated a high degree of correlation with published sample size and power tables (see the equations section). If an activation key is purchased then power and sample number tables can be generated for given alpha values so the validity of the algorithms can be examined.
What equations / methods are used to calculate power / sample sizes?
Please see the equations section.
What will be the major change between versions 1 and 2?
You will have to wait and see! However, if you buy a key for version 1 it will work with version 2!
When will version 2 be released?
At some point!
How was Power on X developed?
Power on X was developed on a PowerBook and an iMac (both 'lamp' and 'slot-loading"), and tested on an iBook (old 'clamshell' type), a PowerBook and several iMacs. Development was carried out using the development tools (Project Builder and Interface Builder) and tested with MallocDebug and ObjectAlloc.
Why was Cocoa used?
It is the future of the Mac! It also allows access to all the new features which are part of Mac OS X.
Will there be a Mac OS 9 version of Power on X?
No! Web Photos was developed for Mac OS X and above. There are no plans to port it to Mac OS 9. However, there are other programs available that perform power calculations and run on Mac OS 9.
Will there be a Windows version of Power on X?
No!
If you have any further questions please e-mail: faemail@mmisoftware.co.uk