# What is conditional variance in GARCH model?

## What is conditional variance in GARCH model?

A process, such as the GARCH processes, where the conditional mean is constant but the conditional variance is nonconstant is an example of an uncorrelated but dependent process. The dependence of the conditional variance on the past causes the process to be dependent.

How do you calculate conditional variance?

Estimating conditional variance y|x

1. Generate a new dataset (xi,y2i).
2. Find g(x)=argming∑i||g(xi)−y2i||22.
3. We know that the minimiser g=E[y2|x].
4. Compute the conditional variance estimate as var(y|x)=g(x)−f(x)2 and use this as an estimate of the uncertainty in the prediction f(x).

### What is conditional volatility in GARCH?

Conditional volatility is the volatility of a random variable given some extra information. In the GARCH model, the conditional volatility is conditioned on past values of itself and of model errors. Unconditional volatility is the general volatility of a random variable when there is no extra information.

What is a conditional variance model?

In probability theory and statistics, a conditional variance is the variance of a random variable given the value(s) of one or more other variables. Conditional variances are important parts of autoregressive conditional heteroskedasticity (ARCH) models.

#### What is Arima GARCH model?

ARIMA/GARCH is a combination of linear ARIMA with GARCH variance. We call this the conditional mean and conditional variance model. This model can be expressed in the following mathematical expressions. The general ARIMA (r,d,m) model for the conditional mean applies to all variance models.

How do you find the conditional variance example?

Conditional Variance: Similar to the conditional expectation, we can define the conditional variance of X, Var(X|Y=y), which is the variance of X in the conditional space where we know Y=y. If we let μX|Y(y)=E[X|Y=y], then Var(X|Y=y)=E[(X−μX|Y(y))2|Y=y]=∑xi∈RX(xi−μX|Y(y))2PX|Y(xi)=E[X2|Y=y]−μX|Y(y)2.

## Is covariance the same as conditional variance?

Variance and covariance are mathematical terms frequently used in statistics and probability theory. Variance refers to the spread of a data set around its mean value, while a covariance refers to the measure of the directional relationship between two random variables.

What is the difference between conditional and unconditional?

A conditional offer letter has specific conditions with it. It means you need to have certain grades or marks for the same, whereas unconditional offer letter has no conditions with it, and reflects that your grades, whether high or low, have been accepted by the University.

### What is the difference between an unconditional and conditional average?

For a random variable yt, the unconditional mean is simply the expected value, E ( y t ) . In contrast, the conditional mean of yt is the expected value of yt given a conditioning set of variables, Ωt. A conditional mean model specifies a functional form for E ( y t | Ω t ) . .

How do you calculate conditional mean?

The conditional expectation (also called the conditional mean or conditional expected value) is simply the mean, calculated after a set of prior conditions has happened….Step 2: Divide each value in the X = 1 column by the total from Step 1:

1. 0.03 / 0.49 = 0.061.
2. 0.15 / 0.49 = 0.306.
3. 0.15 / 0.49 = 0.306.
4. 0.16 / 0.49 = 0.327.

#### How to calculate the conditional variance of a GARCH model?

As far is know the term conditional variances is used only in GARCH models. So, I assume that in order to calculate these variances one has to use a GARCH Model for the returns. First, one has to calculate the returns r t = ln ( p t − 1). Then, the returns should be centered via r ^ t = r t − r ¯ (quite unsure if this meant by centered).

How to calculate the conditional variance of a centered return?

Fig. 2 shows the conditional variances of the centered returns of the series of prices under study. As far is know the term conditional variances is used only in GARCH models. So, I assume that in order to calculate these variances one has to use a GARCH Model for the returns.

## Why does GARCH model have conditional heteroskedasticity?

The variance of the error term in GARCH models is assumed to vary systematically, conditional on the average size of the error terms in previous periods. In other words, it has conditional heteroskedasticity, and the reason for the heteroskedasticity is that the error term is following an autoregressive moving average pattern.

Can a GARCH model be combined with an arch model?

As we have seen, an AR(1) process has a nonconstant conditional mean but a constant conditional variance, while an ARCH(1) process is just the opposite. If both the conditional mean and variance of the data depend on the past, then we can combine the two models. model with any of the GARCH models in Section 18.6.