Variance is the measure of the degree to which data points differ from their mean. According to Layman the term “variance” is the measurement of the extent to which the numbers (numbers) are distributed from their average (average) number.

Variance is the term used to determine the expected deviation from the actual value. Thus, the variance is based on how much standard deviation is present in the data set.

The higher the value of variance is, the data will be more scattered from its mean . And If the variance is minimal or low the data has less scattering from the mean. Thus, it is an indicator of the spread of data.

To solve problems, the formula to calculate variance is provided by:

Vari (X) = E( X +


In simple terms, it means that variance is the expected variance of the squared variation in a randomly selected set data from its mean. Here,

The random variable X

“u” is equal to E(X) thus this equation could also be written as

Var(X) = E[(X – E(X))2]

Var(X) = E[ X2 -2X E(X) +(E(X))2]

Var(X) = E(X2) -2 E(X) E(X) + (E(X))2

Var(X) = E(X2) – (E(X))2

Sometimes, the covariance of a random variable is interpreted by the term “variance” the variable. Symbolically,

Var(X) = Cov(X, X)


We already know that it is the sum of the standard deviation i.e.,

Variance = (Standard deviation)2= s2

Extra Considerations

You may also apply that formula in order to determine the variance in other areas that are not investments or trading, but with a few minor changes. When calculating an estimate of a sample variance in order to determine the population variance the denominator in the equation of variance becomes N – 1. This ensures that the estimation is fair and doesn’t underestimate the variance of the population.

Advantages and disadvantages of Variance

Statistics use variance to determine the way that individual numbers are related to one another within a set, as opposed to employing more general mathematical methods such as grouping the numbers in quartiles. The benefit to using variance is it considers any deviation in the direction of the median as same, regardless of the direction they take. The squared deviations can’t add up to zero and create the impression of having no variation whatsoever on the basis of the numbers.

One disadvantage of variance but it adds importance to outliers. These are numbers that are far from the average. The process of quadrupeding these numbers can cause skews to the information. Another issue with applying variance to data is the fact that it’s difficult to interpret. It is often used to calculate its square root. the value, which is what the average deviation is of the set. As mentioned above investors can utilize standard deviation to gauge the consistency of returns over time.

In some instances risks or volatility can be expressed in terms of an average deviation instead of a variance since the former is usually more readily understood.

A Sample of Variance

Here’s a hypothetical scenario to illustrate how variance operates. Let’s suppose that the returns for stocks for Company ABC are 10% in Year 1 and 20% in Year 2 and -15% in Year 3. The average of the three returns is five percent. The variations from each one and between the mean are 5%, 15 percent and -20% for each year.

The result of dividing these deviations is 0.25 percent, 2.25%, and 4.00 percent according to. If we combine those squared deviations we will get an overall figure of 6.5 percent. If you divide the total of 6.5 percent by one less than the number of returns within this data set since it is an example (2 equals 3-1) that gives an average of 3.25 percent. By taking the square root of the variance gives 18.5% as the average of returns.

Difference Between Standard Deviation and Variance

Below, the comparison of the differences between the standard deviation and the variance deviation is provided below in greater detail:

Variance Difference as well as Standard Deviation


Standard Deviation

Variance simply defined by the number that explains how varied the data are.

S.D could be described as the observational data taken into account are measured using dispersion in a data set.

Variance is nothing more than the average of all the deviations in squares.

Standard Deviation is defined as the root of the mean square deviation

Variance is expressed as squared units.

Standard deviations are expressed in the same units as the information available.

Variance mathematically identified in math as (s 2)

S.d mathematically referred to as (s)

The degree of variation is a good indication of the people who are spread out in a.

The standard deviation can be the best indicator of the findings in a set of data.