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.
The variance is computed as the average squared deviation of each number from its mean. For example, for the numbers 1, 2, and 3, the mean is 2 and the variance is: . The formula (in summation notation) for the variance in a population is. where Î¼ is the mean and N is the number of scores. When the variance is computed in a sample, the statistic. (where M is the mean of the sample) can be used. SÂ² is a biased estimate of ÏÂ², however.