How to Predict the Performance of a String

The experiment involved an eight-bit string prediction problem. i want the computer to learn this relationship between the bits but i don't tell it this relationship, instead what I do is pick a one of the bits at random just any one of them and then i take say two of the eight-bit strings for each bit. Usually it'll sort of use that with two examples out of the possible 16 and more often than not it'll be wrong right. It might just be that this bit is always just tends to be minus something it's bit random so i keep iterating trying different combinations of eight- Bit strings and see what the average performance is over many many iterations.