## How do you calculate conditional expectations?

The conditional expectation, E(X |Y = y), is a number depending on y. If Y has an influence on the value of X, then Y will have an influence on the average value of X. So, for example, we would expect E(X |Y = 2) to be different from E(X |Y = 3).

## What is conditional expectation function?

In probability theory, the conditional expectation, conditional expected value, or conditional mean of a random variable is its expected value – the value it would take “on average” over an arbitrarily large number of occurrences – given that a certain set of “conditions” is known to occur.

**What does it mean to condition on a sigma-algebra?**

Conditioning with respect to sigma-algebras be an event. We say that a random variable is a conditional probability of with respect to the sigma-algebra if and only if. It can be shown that this definition is equivalent to our definition of probability conditional on a partition.

### How do you calculate conditional distribution?

First, to find the conditional distribution of X given a value of Y, we can think of fixing a row in Table 1 and dividing the values of the joint pmf in that row by the marginal pmf of Y for the corresponding value. For example, to find pX|Y(x|1), we divide each entry in the Y=1 row by pY(1)=1/2.

### What is the conditional expectation function of the population regression function?

E(Y | Xi) = f (Xi) is known as conditional expectation function(CEF) or population regression function (PRF) or population regression (PR) for short. In simple terms, it tells how the mean or average of response of Y varies with X.

**Are sigma algebras countable?**

The collection of subsets of X which are countable or whose complements are countable is a σ-algebra (which is distinct from the power set of X if and only if X is uncountable). This is the σ-algebra generated by the singletons of X. Note: “countable” includes finite or empty.

## Are all sigma algebras algebra?

σ-algebras are a subset of algebras in the sense that all σ-algebras are algebras, but not vice versa. Algebras only require that they be closed under pairwise unions while σ-algebras must be closed under countably infinite unions.

## What is linearity of expectation?

Linearity of expectation is the property that the expected value of the sum of random variables is equal to the sum of their individual expected values, regardless of whether they are independent.

**What is conditional expectation function of the population regression function?**