> definitions of data.frames vs. matrix vs vectors. I have read many R. > tutorials, and looked over ump-teen 'cheat' sheets and have found that. > no one has articulated a really good definition of the differences. > between 'data.frames', 'matrix', and 'arrays' and even 'factors'.
Medical Definition of Tumor Our Tumor (Grade) Main Article provides a comprehensive look at the who, what, when and how of Tumor (Grade) Tumor: An abnormal mass of tissue. Tumors are a classic sign of inflammation, and can be benign or malignant (cancerous). There are dozens of different types of tumors. Their names usually reflect the kind of tissue they arise in, and may also tell you something about their shape or how they grow.
Brain tumors, either malignant or benign, are tumors that originate in the cells of the brain. A tumor is an abnormal growth of tissue. A benign tumor does not contain cancer cells and usually, once removed, does not recur.