Panic attack symptoms are a common reaction. Other anxiety disorders include: agoraphobia, separation anxiety disorder and substance/medication-induced anxiety disorder involving intoxication or withdrawal or medication treatment.
Statistics and Probability Dictionary. Select a term from the dropdown text box. The online statistics glossary will display a definition, plus links to other related web pages. Select term: Variance. The variance is a numerical value used to indicate how widely individuals in a group vary. If individual observations vary greatly from the group mean, the variance is big; and vice versa. It is important to distinguish between the variance of a population and the variance of a sample.
This article is about the mathematical concept. For other uses, see Variance (disambiguation). In probability theory and statistics, variance is the expectation of the squared deviation of a random variable from its mean, and it informally measures how far a set of (random) numbers are spread out from their mean. The variance has a central role in statistics.