By convention, specific symbols represent certain sample statistics. For example, 1  x refers to a sample mean. 2  s refers to the standard deviation of a sample. 3  s 2 refers to the variance of a sample. 4  p refers to the proportion of sample elements that have a particular attribute.or example, 1  P refers to a population proportion; and p, to a sample proportion. 2  X refers to a set of population elements; and x, to a set of sample elements. 3  N refers to population size; and n, to sample size.
The brain is one of the most important organs in the body and gives humans the capacity for language, art, and rational thought. A brain surgeon, or neurosurgeon, is a doctor that performs surgery on the nervous system, particularly the brain. He or she will also treat a wide range of problems affecting the central nervous system is the job of a brain surgeon.
Brain surgeons not only need skill, stamina and dexterity, but also have to keep their cool in highly emotional situations. Interview several neurosurgeons. Get into the best school you can (see 150 Get Into a Top College or University) and earn a four-year pre-med degree. To deliver the best care, you need to stay on top of medical advances throughout your career. 2  Surgeons earned a median annual income of $255,438 in 2002. 3  Fifty years ago, half of brain surgeries were fatal.