## The definition of variance

Variance is a measurement of how spread out numbers are. It is the average of the squared deviations from the mean. The positive square root of the variance is called the standard deviation.

### What is a variance?

In statistics, variance is a measure of how to spread out a data set is. It is calculated as the average of the squared differences from the mean. The positive square root of the variance is called standard deviation.

A variance is a useful tool for measuring risk in investments. A higher variance means that returns are more volatile and thus riskier. For example, stocks tend to have higher variances than bonds.

Variance can also be used to measure how well a statistical model fits a data set. A model with high variance is said to be overfit, meaning it does not generalize well to new data.

### How is variance used?

In statistics, variance is a measure of how far a set of numbers is spread out from its mean. A large variance indicates that the data points tend to be far from the mean, while a small variance indicates that they tend to be close to the mean.

The standard deviation is simply the square root of the variance. It is usually more convenient to work with the standard deviation because it has the same units as the original data.

Variance is used in a variety of settings, including:

- To measure how much return you can expect from an investment
- To measure how much a stock price fluctuates over time
- To measure how effective a medical treatment is
- To measure how effective an advertising campaign is

The positive square root of variance

The variance is a measure of how far a set of numbers is spread out. The positive square root of variance is called the standard deviation. It is a measure of how far away each number in a set is from the mean.

What is the positive square root of variance?

The positive square root of variance is called the standard deviation. It is a measure of how spread out the values are.

### How is the positive square root of variance used?

The positive square root of variance is called the standard deviation. Standard deviation is a statistical measurement that is used to tell how widely dispersed a group of data points is. A low standard deviation means that the data points are clustered closely together, while a high standard deviation means that the data points are spread out.