Starting screen When you call gretl the following screen would - - PowerPoint PPT Presentation

Short intro to Gretl software Short intro to Gretl software

Free software for econometrics http://gretl.sourceforge.net/

Starting screen

• When you call gretl the following screen

would appear No active part of menu are would appear. No active part of menu are typically in light shadow.

Opening (data) file

• Click on menu item File, Open Data. You can

also open previously used files, start new also open previously used files, start new data...

After data are opened..

• The screen looks like this. Good data files have

also description of variables. Keep it in mind!!! also description of variables. Keep it in mind!!!

We always compute the statistics for highlighted variable(s) highlighted variable(s)

• As in your operating system you select

i bl I Wi d CTRL d

• variables. In Windows, you can use CTRL and

Click of the mouse..

You can do any analysis, transformation descriptive stats transformation, descriptive stats

• For example we want to see descriptive

i i ( i i i ) statistics (means, variances, minimum...)

On click you get what you marked

• In this case all basic descriptive statistics

Defining a new variable

• In this case menu item Add, define new

i bl variable

Defining a new variable

Or menu item Variable Variable, define new variable variable

Defining a new variable

• We can write any formula to define new var.
• Here we define wage per week, i.e. Total wage

divided by total number of week worked.

It is good to add a label (or description of variable) description of variable)

• Once you highlight one variable, left mouse

li k ( i d ) i click (windows) can get you into a menu:

On a variable, right mouse click

Making a discrete variable…

Making a useful transformations (squares, logs..) Definitions of new variables Working with restrictions

Highlighting more variables …

• On click of the right mouse offers:

Highlighting more variables …

• On click of the right mouse offers:

Test of equality of two means

• Select from menu: Tools,

Test calculator.

• Fill the values for each

sub-sample: here is an p example Do not forget to hit g ENTER after you specify each variable Easy control, you have y y different mean & sample

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Example Example

Reading Regression in gretl

• Menu: Model,

Ordinary least squares – Dependent variable i h t d l is what you model – Independent variables are variables are factors used in describing (price) describing (price) – After your you make your make your selection, click OK

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Running a linear regression model

Additional analysis … example, confidence intervals

Working with graphs … confidence ellipse On right mouse click We can go back and modify the model

Setting and testing for multiple restrictions Results of the test for linear restrictions

History of all commands – command log What you see in a command log

Saving command log and using it as a script Direct command entry – gretl console

Last but not least Command reference – again on a click

Icons on the bottom of the page: Calculator Script Command reference XY p Console S i XY graphs Session Icons OLS Models Functions User’s Open Dataset guide

Icon view: Useful for descriptive statistics