Let’s start with a translation in English: The variance of historical returns is equal to the sum of squared deviations of returns from the average (R) divided by the number of observations (n) minus 1. (The large Greek letter sigma is the mathematical notation for a sum.)

**Variance** is **calculated** by taking the differences between each number in the data set and the mean, then squaring the differences to make them positive, and finally dividing the sum of the squares by the number of values in the data set.

Subsequently, question is, how do you calculate stock return over time? **How-To Calculate Total Return**

- Find the initial cost of the investment.
- Find total amount of dividends or interest paid during investment period.
- Find the closing sales price of the investment.
- Add sum of dividends and/or interest to the closing price.
- Divide this number by the initial investment cost and subtract 1.

Also Know, what is the variance of the stock’s returns?

The **variance** measures the differences between the annual **returns** of the **stock**: the higher the **variance**, the more volatile the **stock**. In order to calculate the **variance**, you first have to figure out the annual **returns** for each year, and then the overall average.

What is the formula of variance?

To calculate **variance**, start by calculating the mean, or average, of your sample. Then, subtract the mean from each data point, and square the differences. Next, add up all of the squared differences. Finally, divide the sum by n minus 1, where n equals the total number of data points in your sample.

### What is a good portfolio variance?

The most important quality of portfolio variance is that its value is a weighted combination of the individual variances of each of the assets adjusted by their covariances. This means that the overall portfolio variance is lower than a simple weighted average of the individual variances of the stocks in the portfolio.

### What is a good variance?

All non-zero variances are positive. A small variance indicates that the data points tend to be very close to the mean, and to each other. A high variance indicates that the data points are very spread out from the mean, and from one another. Variance is the average of the squared distances from each point to the mean.

### What exactly is variance?

The variance in probability theory and statistics is a way to measure how far a set of numbers is spread out. Variance describes how much a random variable differs from its expected value. The variance is defined as the average of the squares of the differences between the individual (observed) and the expected value.

### Why is variance important?

It is extremely important as a means to visualise and understand the data being considered. Statistics in a sense were created to represent the data in two or three numbers. The variance is a measure of how dispersed or spread out the set is, something that the “average” (mean or median) is not designed to do.

### Can the variance be negative?

Negative Variance Means You Have Made an Error As a result of its calculation and mathematical meaning, variance can never be negative, because it is the average squared deviation from the mean and: Anything squared is never negative. Average of non-negative numbers can’t be negative either.

### Is variance a standard deviation?

6 Answers. The standard deviation is the square root of the variance. The standard deviation is expressed in the same units as the mean is, whereas the variance is expressed in squared units, but for looking at a distribution, you can use either just so long as you are clear about what you are using.

### Is volatility the same as variance?

Variance is a measure of distribution of returns and is not neccesarily bound by any time period. Volatility is a measure of the standard deviation (square root of the variance) over a certain time interval. In finance, variance and volatility both gives you a sense of an asset’s risk.

### How do you interpret a sample variance?

Definition of Sample Variance In order to understand what you are calculating with the variance, break it down into steps: Step 1: Calculate the mean (the average weight). Step 2: Subtract the mean and square the result. Step 3: Work out the average of those differences.

### What is the variance of a portfolio?

Portfolio variance is a measure of the dispersion of returns of a portfolio. It is the aggregate of the actual returns of a given portfolio over a set period of time. Portfolio variance is calculated using the standard deviation of each security in the portfolio and the correlation between securities in the portfolio.

### What is the difference between standard deviation and variance?

Key Takeaways. Standard deviation looks at how spread out a group of numbers is from the mean, by looking at the square root of the variance. The variance measures the average degree to which each point differs from the mean—the average of all data points.

### Is variance a percentage?

A variance is an indicator of the difference between one number and another. You calculate the percent variance by subtracting the benchmark number from the new number and then dividing that result by the benchmark number. In this example, the calculation looks like this: (150-120)/120 = 25%.

### Is standard deviation a percentage?

The relative standard deviation (RSD) is often times more convenient. It is expressed in percent and is obtained by multiplying the standard deviation by 100 and dividing this product by the average.