Two definitions of Machine Learning are offered. Arthur Samuel described it as :”the field of study that gives computer the ability to learn without being explicitly programmed.” This is an older, informal definition.
Tom Mitchell provides a more modern definition: “A computer program is said to learn from experience E with respect to some class of tasks T and performance measure P, if its performance at tasks in T, as measured by P, improves with experience E.”
Example: playing checkers.
E = the experience of playing many game of checkers
T = the task of playing checkers
P = the probability that the program will win the next game
In general, any machine learning problem can be assigned to one of two board classification:
Supervised learning and Unsupervised learning.
原文：http://www.cnblogs.com/zwx19961130/p/6268051.html