Anxiety disorders can be seen with other mental health conditions, such as: 1  Depression. 2  Substance abuse. 3  ADHD. 4  Eating disorders. 5  Trouble sleeping.
A variance has several meanings in business. In an accounting sense, a variance is the difference between an actual amount and a pre-determined standard amount or the amount budgeted. In a statistical sense, a variance is a measure of the amount of spread in a distribution.
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.