## What demeaned data?

Demeaning data means subtracting the sample mean from each observation so that they are mean zero.

### What are fixed effects variables?

Fixed effects are variables that are constant across individuals; these variables, like age, sex, or ethnicity, don’t change or change at a constant rate over time. They have fixed effects; in other words, any change they cause to an individual is the same.

**What is panel data example?**

Panel data, sometimes referred to as longitudinal data, is data that contains observations about different cross sections across time. Examples of groups that may make up panel data series include countries, firms, individuals, or demographic groups.

**What is Xtreg Stata?**

The Stata command to run fixed/random effecst is xtreg. In this case “country” represents the entities or panels (i) and “year” represents the time variable (t). The note “(strongly balanced)” refers to the fact that all countries have data for all years.

## What is the mean of a demeaned variable?

Hence, within each subject, the demeaned variables all have a mean of zero. For time-invariant variables, e.g. gender, the. Panel Data: Very Brief Overview Page 4 demeaned variables will have a value of 0 for every case, and since they are constants they will drop out of any further analysis.

### How are demeaned variables used in linear regression?

In the case of quantitative dependent variables analyzed in linear regression models, a commonly used approach is Demeaning variables. The within-subject means for each variable (both the Xs and the Y) are subtracted from the observed values of the variables. Hence, within each subject, the demeaned variables all have a mean of zero.

**Which is the intercept of the demeaned variable?**

Imagine that your variable is equal to the mean, hence x_i-x_bar will be 0. Then the coefficient of the demeaned variable will be multiplying with 0. What is left untouched is the intercept. Hence the individual intercept (I think in you case alpha_i) provides the (expected) outcome of the i with characteristics equal to the mean.

**How is entity demeaned used in fixed effect regression?**

The entity-demeaned here is really just subtracting each observation by its entity mean value to take out those unobservable entity-unique-but-time-invariant variables impact from our outcome variable. I will use the famous beer tax data to illustrate the steps in python as below: