Anxiety can often make these related conditions worse, so talk with a mental health care professional if anxiety begins to interfere on a daily basis.
In probability theory and statistics, the variance of a random variable is a measure of its statistical dispersion, indicating how far from the expected value its values typically are. The variance of a real-valued random variable is its second central moment, and it also happens to be its second cumulant.
Variance and covariance are mathematical terms frequently used in statistics, and despite the similar sounding names they actually have quite different meanings. A covariance refers to the measure of how two random variables will change together and is used to calculate the correlation between variables. The variance refers to the spread of the data set â how far apart the numbers are in relation to the mean, for instance.