# Normal Distribution

Normal distribution, alternatively referred to as the Gaussian distribution, signifies a probability ordering, where the data close to the mean are more prevalent than the further ones. In the case of using graphs, the concept is presented as a bell curve.

## Essence of Normal Distribution

In fact, the normal distribution plays a crucial role in many fields of knowledge, including stock market monitoring, price following and probability determination. There are two major parameters in regards to the standard normal distribution. The first entails a mean, while the second presupposes a standard deviation.

The concept of normal distribution is based on the Laplace-Levy theorem (CLT). It suggests that the sum of independent random variables, selected from almost any ordering, has a distribution close to normal. Notably, a finite variance should be anticipated. The CLT corrects a non-normal spreading to the normal distribution.

In certain cases, the normal distribution can be mixed with a symmetrical one. But these are two different notions. Symmetrical distribution is premised on the extreme values that are equally frequent. In other words, an allocation line creates two mirrored images.

**The normal distribution depends on 4 parameters:**

**mathematical expectation**, or the "gravity center" of the distribution;**variance**, i.e. the degree of dispersion of a random variable relative to the mathematical expectation;**skewness coefficient**, meaning a parameter of the distribution form, which determines its symmetry with respect to the mathematical expectation;**kurtosis coefficient**, which is a distribution parameter that specifies the “sharpness” of the distribution peak.

As for a particular collection of data, the normal distribution places the mean at the center, while standard deviations measure the dispersion over the mean.

## Asymmetry ratio and kurtosis

The data often doesn’t follow the precise image of a bell curve, i.e. the normal distribution. Asymmetry ratio and kurtosis are referred to as criteria of deviation from this ultimate concept. The skewness detects a mismatch of distribution tails: a favorable one has findings that deflect upwards from the mean. The adverse is also valid for a below skew.

While asymmetry ratio is associated with tail imbalance, kurtosis is connected with tail endings. And it doesn’t matter whether these endings are above or below the average.

Speaking about the asymmetry ratio and kurtosis, the monitoring of fixed interest bearing securities, for instance, needs a thorough statistical review to estimate holdings’ volatility in case of modifying interest rates.

Patterns that forecast a moving direction must take into account the mentioned indicators, in order to call the turn of the portfolio yield. Such statistical notions are used to set the price behavior of various derivative tools, for example, stocks, options, along with currency pairs.

## Normal Distribution in financing

As a rule, a standard deviation defines volatility and specifies an expected yield. The smaller indicator implies lower asset risk. The converse is also true. By the way, volatility is the change in the price of an asset over a certain period of time. It designates a range of price fluctuations during the day, week, month, year.

Traders are able to determine closing prices as a differential to the mean. A greater differential between the true cost and the average contemplates a larger standard deviation and, as a result, more volatility.

Costs that vary far can revive to the mean, in order to allow market players to make profit from these fluctuations. At the same time, costs at a small range are sometimes prepared for a breakout.

The instrument for standard deviation trading, which is in widespread use, is Bollinger Bands. This tool is considered a criterion of the volatility set. The indicator is based on the root mean square, or standard deviation. It assists in analyzing how prices are located relative to the normal trading range. The bands also create a corridor within which prices are considered normal.