Date post: | 10-Apr-2017 |
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Economy & Finance |
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Session 1Module Introduction and Getting Started with Stata
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Lic. David A. Condori Tantani
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Introduction
Welcome Housekeeping Introductions
Name, job, district, team
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Lic. David A. Condori Tantani
Module Overview3
Module objectives are to provide you with
• Skills in data analysis
• Keeping in mind the analysis objectives
• While learning the use of a specialised statistical software package Stata
There will be a strong emphasis on conductingmeaningful analyses and on the interpretationof the results.
Lic. David A. Condori Tantani
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Module content
Data management Data entry principles and practices
using Epi Info designing data capture screens, labelling and entering data, etc.
Simple statistical analysis in Epi Info and using the statistics package, Instat.
Report writing.
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Duration and timetable
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Morning Afternoon
Day 1 Getting started with Stata Continued
Day 2 Tables Project work part 1
Day 3 Graphs Project work part 2
Day 4Reviewing inference: estimation and confidence intervals
Reviewing inference: Hypothesis testing
Day 5 Tests of association in 2-way tables Sampling weights
Day 6 Project work part 3: writing the report Putting it all in context
Lic. David A. Condori Tantani
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Module Learning Objectives
At the end of the module, participants will : appreciate the power of Stata as a statistical package be able to undertake elementary data management
and statistical analyses in Stata have updated their practical knowledge of the key
statistical inference concepts of estimation and hypothesis testing
be able to produce graphs and tables using Stata, have sufficient knowledge of Stata to be able to work
independently to produce other analyses6
Lic. David A. Condori Tantani
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Prerequisites
Completion of Modules 1 and 2At least a theoretical knowledge of statistical inference
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Resources
Stata software - version 10 This should be installed already It may need updating and a Stata “package” adding – see later
slides Guide to survey data analysis using Stata
Part 1 (Chapters 1 to 10) is used here Part 2 (Chapters 11 to 20) is supplied for reference
Inference guide Used particularly in Sessions 7 and 8
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Concepts more than software
The emphasis is on the concepts of data analysis and statistical inference Using Stata
Rather than just on Stata itself Here we largely use the menus and dialogues Though ways of using and reading commands are introduced
Software is now easy to master It is the statistical concepts that benefit from a course
Lic. David A. Condori Tantani
Learning objectives – sessions 1 and 2 These two sessions are about Stata
Participants will be able to: Load and save data Explore data
Using describe, codebook, summarize, etc Calculate new variables
Using generate, recode, etc Add labels to variables and to levels of a factor Create subsets of data using drop and keep
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Lic. David A. Condori Tantani
Session Contents11
In this session we look in particular at:
• Windows and menus in Stata
• Opening Stata data files
• Stata dialogues
• Typing and editing commands
• Using Stata as a calculator
• Exiting Stata
Lic. David A. Condori Tantani
The four Stata windows12
Review
Stata Results
Variables
and window for typing Stata commands
The Stata menus and toolbar The three most important menus
Data (for organising and managing the data), Graphics (for visual exploration & presentation), Statistics (for analysis).
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Data, Graphics, Statistics
Check Stata is up-to-date Use Help => Official updates
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If updating is needed, either:
Do it automatically if you are connected to the internet
Or use the files on the CD/DVD that are under Stata resources
The Data and Graphics Menus15
Lic. David A. Condori Tantani
Your turn Click on several menus and explain their
usage to your neighbour You can deduce the menu from the logic of the
task e.g. to draw a graph you go to the graphics
menu!
Which menu would you probably need to use to: save data? sort a data set? produce a bar chart? tabulate the data?
Check by finding the dialogue in Stata
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Lic. David A. Condori Tantani
Stata guide Section 1.2
You use Stata as a calculator Go through this section together Check the buttons at the bottom of the dialogue
They are the same on all dialogues
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Lic. David A. Condori Tantani
Using Stata as a calculator
To perform calculations, useData Other utilities Hand calculator
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Type 2+3 into the Expression slotPress the Submit button
See answer in Results Window, and appearance of corresponding command in both the Results and Review windows.
Results from the dialogue
You can get back to any dialogue box by typing db in front of the command name. e.g. db display
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Creating an expression20
Click create and then complete the resulting expression builder dialogue box.
Or type:display ln(10)
Stata guide Section 1.3
From this point you use a dataset that is supplied Check that you have a working directory And that it has the files for this module
Copy them in, if not They are on the CD/DVD under Stata resources You could install the Stata package as well if you wish.
Then use Files => Change working directory To set this directory for the future
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Lic. David A. Condori Tantani
Opening a Stata data file Use the menu sequence
File, Open… select (highlight) the file named K_combined_short.dtaand click on Open
This will load the data from the Kenya socio-economic survey into Stata
Look at the Variables Window. What do you observe?
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Lic. David A. Condori Tantani
Options within the Data menu 23
Lic. David A. Condori Tantani
An example of a dialogue box 24
Dialogue results from using the menu sequence Data, Describe data,
Describe data contents (codebook)
In the codebook dialogue box…
The Submit button instructs Stata to execute the command, leaving the
dialogue box visible. The OK button does the same,
but closes the dialogue box. Cancel closes the dialogue box
without submitting the command to Stata. The R button resets the dialogue box
to its empty form. ‘?’ gives help on the command
associated with the dialogue box. The word “codebook” at the top of the dialogue
shows “codebook” is the command that will be generated
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Another dialogue box 26
Dialogue results from using the menu sequence Data, Describe data, Summary statistics
Results from codebook and summarize27
Your turn
In Chapter 1 of the Stata guide, go through
Section 1.3 Section 1.4 Section 1.5
Ask a resource person if you are unclear aboutany parts of the above sections.
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Lic. David A. Condori Tantani
Review29
What do each of these buttons do?
Menus (and corresponding commands) used so far:•display•describe•codebook•list•generate•replace
•by/if//in
What does each one do?
Your turn again
In Chapter 1 of the Stata guide, go through
Section 1.6 Section 1.7 Section 1.8
Ask a resource person if you are unclear aboutany parts of the above sections.
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Lic. David A. Condori Tantani
Review again
Explain to a neighbour why: (3<4) gives the value 1 in Stata (3>4) gives the value 0
They then explain to you why the expression: 1 + (age>24) + (age>60) Recodes a column into the values 1, 2 or 3
(Hint – see Section 1.6 Fig 1.19 and 1.20 if you need help)
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Lic. David A. Condori Tantani
Typing and editing commands
Professional use of Stata for data analysis benefits by some use of Stata commands
These are typed into the Command Window To execute a command just press <Enter>.
To edit a previous command: Click on it in the review window, or use the Page-Up key – perhaps repeatedly.
In the Results Window A “dot” appears in front of executed commands whether generated by a dialogue, or by typing the command.
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Command for listing data
In the command window, typing list region district household cluster
will show the contents of each of the variables region, district, household and cluster. (Note: Stata is case sensitive)
Pressing the GO button (see Stata menu bar) or the space bar allows you to scroll down the pageTo stop the display, press the red break icon button or press the letter q on your keyboard.To exit Stata, use:
File Exit
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Lic. David A. Condori Tantani
Your turn yet again
In Chapter 2 of the Stata guide, go through
Sections 2.1 and 2.2 (You can go further if you have time)
If you have your own data And it is not already in a Stata file, then: In Chapter 3 of the Stata guide, go through
Sections 3.2.1, 3.2.2, 3.2.3 And discuss importing with the resource
persons
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Lic. David A. Condori Tantani
… and finally…
Consider a data set from your own district or ministry that is available as an Excel file.
Follow procedures similar to those in Section 3.2.3 of the Stata Guide, to load your Excel data set into Stata.
Save your data as a Stata file, giving it an appropriate name and noting the directory on your computer where it has been saved.
Note: You will return to this data set in sessions that follow.
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