1. A method of determining whether waking or any of a plurality of defined types of sleep including first, second, third, fourth and fifth types of sleep occur in data gathered from a subject, said determinations being made based on such data gathered and various criteria, said method comprising: obtaining electroencephalographic signal data and electromyographic signal data from said subject; providing a representation of frequency content of said electroencephalographic signal data and presenting said electroencephalographic frequency content representation on a display means; providing a representation of signal strength of said electromyographic signal data and presenting said electromyographic signal strength representation on said display means; providing selected frequency and signal strength values at least one of which is greater than values of a portion and less than values of another portion of a corresponding one of said electroencephalographic frequency content representation and said electromyographic signal strength representation; and determining, based on said electroencephalographic signal data and said electromyographic signal data and on said selected frequency and signal strength values, whether waking or which of any of said types of sleep have been experienced by said subject during said obtaining of said electroencephalographic signal data and electromyographic signal data.