Variance is a statistical measure that shows how much a set of numbers differs from the average (mean) of that set. It helps us understand the spread or dispersion of data points. For example, if we have the ages of a group of people, a low variance means most ages are close to the average, while a high variance indicates a wider range of ages. In practical terms, variance is useful in many fields, such as finance and science. For instance, in finance, investors look at the variance of stock returns to assess risk. A higher variance suggests more uncertainty, while a lower variance indicates stability.