a numerical measureof the chance that something will happen, expressed as a number between 1 (certainty) and 0(impossibility). A probability of 0.05 is typically used in psychological investigationsto represent the probability of an effect found occurring if the nullhypothesis is true, ie. The results are purely due to chance factors.
refers to a group of five disorders characterised by delays inthe development of multiple basic functions includingsocialisation andcommunication. The most commonly known PDD is autism.