Sample variance formula The population variance is written as σ 2, where σ is the population standard deviation. Population variance formula The mean is the average of the data, whereas the variance is a measure of how far each value in the data set is from the mean. The mean is a measure of centre and the variance is a measure of spread. The variance formula lets us measure this spread from the mean of the random variable. Understand the variance formula with examples and FAQs. In probability theory and statistics, the variance formula measures how far a set of numbers are spread out. It is a numerical value and is used to indicate how widely individuals in a group vary. If individual observations vary considerably from the group mean, the variance is big and vice versa. A variance of zero indicates that all the values are identical. It should be noted that variance is always non-negative- a small variance indicates that the data points tend to be very close to the ... Variance Symbol The symbol for variance is typically represented by the Greek letter sigma squared (σ²) when referring to the population variance . For sample variance , it is often denoted by s². Formula for Calculating Variance The formula used for calculating the Variance is discussed in the image below: We will explain both formulas in detail below, covering the population and sample cases.
