Gereltuya Altankhuyag, LecturerStatistician, UNSIAP

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STATA Third group training course in application
of information and communication technology to
production and dissemination of official
statistics 10 May 11July 2007
Gereltuya Altankhuyag, Lecturer/Statistician,
UNSIAP gereltuya_at_unsiap.or.jp
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Basic commands of graphics

• The commands that draw graphs are

command description --------------
--------------------------------------------------
------ graph twoway scatterplots, line
plots, etc. graph matrix scatterplot
matrices graph bar bar
charts graph dot dot
charts graph box box-and-whisker
plots graph pie pie
charts other more commands to draw
statistical graphs -------------------------------
---------------------------------------
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Basic commands of graphics

• The commands that save a previously drawn graph,
  redisplay previously saved graphs, and combine
  graphs are
• command description
• ------------------------------------------------
  ----------------------
• graph save save graph to disk
• graph use redisplay graph
  stored on disk
• graph display redisplay graph
  stored in memory
• graph combine combine graphs into
  one
• ------------------------------------------------
  ----------------------

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Basic commands of graphics

• The commands for printing a graph are

command description ---------------------------
------------------------------------------- graph
print print currently displayed
graph set printcolor set how colors
are printed graph export export .gph
file to PostScript, etc. ------------------------
----------------------------------------------

• All graphs have extension graph

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Basic commands of graphics

• We can generate plots, e.g. a histogram, with
  STATA
• hist pcexp
• which shows per capita expenditure distnas
  skewed

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Basic commands of graphics

• We can induce normality by transforming
  consumption on a log scale
• gen logpcexp ln(pcexp)
• hist logpce

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Basic commands of graphics
graph bar (mean) pcexp indsave, over(region)
title(Per capita expenditure and individuals'
savings by region)
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Basic commands of graphics
To create a box plot of the household size
vaiable in the hh.dat dataset graph box famsize
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Creation of Do-files and use of Do-file Editor

• Up until now we have used Stata interactively.
• We can do batch processing using Do Files.
• Do files a text file containing commands and
  instruct Stata to execute the commands stored in
  that file.

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Creation of Do-files and use of Do-file Editor

• We can create Do Files using New Do-file Editor

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Creation of Do-files and use of Do-file Editor

• Do-file Editor has menu bar
• Do-file Editor has tool bar

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Creation of Do-files and use of Do-file Editor

• The do-file editor lets you submit several
  commands to Stata at once
• General steps of using the do-file
• Click on the Do-file Editor to open do-file editor

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Creation of Do-files and use of Do-file Editor

• Then type the commands that you wish to submit to
  Stata

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Creation of Do-files and use of Do-file Editor

• Then click on Do current file

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Creation of Do-files and use of Do-file Editor

• If you wish to execute a subset of the lines in
  your do-files, highlight those lines and click
  Do current file button.

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Creation of Do-files and use of Do-file Editor

• Tool bar button Run current file is the same as
  Do current file, but Run suppressess output. It
  is unlikely that you will ever need to use Run
  current file button.

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Creation of Do-files and use of Do-file Editor

• You can put comments in your Do-file
• There are ways to include comments in a Do-file
• Begin with asterisk
• Begin with asterisk and forward slash /
• Place the comment in /../ delimiters
• Place the comment after 2 forward slashes //.//
• Place the comment after 3 forward slashes //////

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Creation of Do-files and use of Do-file Editor
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Creation of Do-files and use of Do-file Editor
Advantage of using / / as a comment indicator
The / / comment can be put anywhere at the
end of a line, even at the middle of a line.
Advantage of using as a comment indicator
The comment indicator can be used
interactively.
The / / can be used only in do-files.
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Creation of Do-files and use of Do-file Editor

• By default Stata assumes that each command is
  ended by the carriage return (cr) (ENTER key
  press).
• If a Syntax with commands is too long to fit in
  one line, we can handle it in 2 ways
• Using delimit
• Using comment signs

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Creation of Do-files and use of Do-file Editor

• using delimit each commandmust end with
  semicolon ()

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Creation of Do-files and use of Do-file Editor

• using comment signs ( / /../ //..//
  //////)

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Creation of Do-files and use of Do-file Editor

• A do-file stops executing when
• The end of the file is reached
• An exit is executed
• An error occurs
• If an error occurs, the remaining commands in the
  do-file are not executed

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Creation of Do-files and use of Do-file Editor

• Retrieve saved do-file
• Click do-file editor
• File
• Open
• Save do-file
• Type in your commands in do-file editor
• File
• Save or Save as
• Saved file takes .do extension

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Creating log-files

• Stata can record your session into a file called
  a log file
• Log file does not start automatically
• You must tell Stata to record your session
• By default, log files are created in a format
  called Stata Markup and Control Language (SMCL)

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Creating log-files

• To create log files using do-files
• Type the followings
• clear
• capture log close
• Specify the location of your log-file in your
  do-file
• log using C\intropov\logfiles\day2, replace
• Specify the start date and time of running
  do-file
• di "Job started at S_TIME on S_DATE"

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Creating log-files

• Write all commands and comments accordingly
• Specify the finishing date and time of running
  do-file
• di "Job ended at S_TIME on S_DATE
• Tell Stata that log is finished
• log close
• Saved file takes .log orsmcl extension
• Note you can make changes in your do-file!!!

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Creating log-files

• To run do-file which contains log
• Click on Edit of the do-file menu bar
• Click Select All all commands and comments will
  be highlighted
• Click Do current file button on tool bar

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Creating log-files
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Creating log-files
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Creating log-files

• To open/retrieve log file click begin log
  button on toolbar

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Creating log-files

• Find you log-file name in relevant folder

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Creating log-files

• Log files have two extensions
• filename.smcl Stata produces this file when you
  open log
• filename.log You can load into your word
  processor. Do-file uses this extension!!!

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Creating log-files

• Choose the extension of your log-file by
  scrolling down Save as type

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Creating log-files

• Then Stata log options window appears and choose
  View existing file (read only)
• The click OK button.

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Creating log-files

• Then you will see all your command records and
  outputs.

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Creating log-files
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Creating log-files

• Append to an existing log-file
• log using filename, append
• Replace an existing log-file
• log using filename, replace

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Use of ado-files

• Stata has two types of commands in terms of use
• Commands built into Stata
• Ado-file commands
• An ado-file is an ASCII text file that contains a
  Stata program.
• Ado-files usually come with help files.

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Use of ado-files

• To determine your command
• which command name
• which ci
• . which ci
• \\Unitednations\Stata9\ado\base\c\ci.ado
• ! version 3.3.15 17mar2005
• Which summarize
• . which summarize
• built-in command summarize

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Use of ado-files

• You can view ado-files
• . viewsource ci.ado

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Use of ado-files

• To know where are ado-files on your PC
• sysdir

sysdir STATA \\Unitednations\Stata9\ UPDATES
\\Unitednations\Stata9\ado\updates\ BASE
\\Unitednations\Stata9\ado\base\ SITE
\\Unitednations\Stata9\ado\site\ PLUS
c\ado\plus\ PERSONAL
c\ado\personal\ OLDPLACE c\ado\
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Use of ado-files

• To run ado-files
• ado-filename varname
• Examples
• ci pcexp
• gini pcexp
• lorenz pcexp

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Use of ado-files

• Examples
• . ci pcexp
• Variable Obs Mean Std. Err.
  95 Conf. Interval
• -------------------------------------------------
  ---------------------------
• pcexp 519 6901.953 192.7895
  6523.207 7280.698
• . gini pcexp
• Gini coefficient .26204428

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Use of ado-files
. lorenz pcexp
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Inputting data

• To input data into Stata, you can use

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Inputting data
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Inputting data
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Inputting data

• Suppose we have an ASCII text dataset as shown
  below

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Inputting data

• Suppose we have a dataset countries.txt in
  c\intropov\data\ folder
• Use the infile command with syntax
• infile variable-list using filename.raw
• In particular, enter
• cd c\intropov\data
• infile y_a y_b y_c using countries.txt

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Inputting data

• When using the infile command for character
  (string) variables (eg.hhcode), we need to
  identify these variables. For instance
• infile y_a y_b y_c str30 domain using
  countries.txt
• For more details regarding infile, enter
• help infile1

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Inputting data

• Suppose we have a dataset try2.txt in
  c\intropov\data folder with the data in
  specific fields

Assumes last line is blank line
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Inputting data

• Use the infix command to input into Stata
• infix domain 1 hhcode 2 age 3-4 using
  try2.txt, clear
• Infix accepts an if statement, e.g.,
• infix if domain 1

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Inputting data

• IMPORTING A WORKSHEET
• Suppose we have an Excel worksheet called
  countries2.xls also in the c\intropov\data
  folder.
• Read the file with Excel, then SAVE AS a comma
  delimited CSV file.
• Enter
• insheet using countries2.csv, clear
• Note Stata cannot read/import data directly from
  Excel!!

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Inputting data

• Thus, Stata can read text files with
• Infile (if the data in text is separated by
  spaces and does not have strings, or if strings
  are just one word, or if all strings are enclosed
  in quotes)
• Infix (fixed format text)
• Insheet (if text file was created by a
  spreadsheet or db program)

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Exporting data

• The command outfile save the data in ASCII
  outsheet in a comma delimited format.
• File ? Export ?Comma or tab- separated data

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Inputting and exporting datasets

• There are third party programs, esp.
  Stat/Transfer and DBMS/COPY, that perform
  translations from one data format (e.g., Excel,
  SAS, SPSS, Stata) to another.

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Inputting and exporting datasets
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Inputting data

• There are 2 ways of creating a new dataset in
  Stata
• 1. Use of Edit
• 1.1 Open the STATA spreadsheet editor

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Inputting data

• 1.2 Enter data into the editor, when done close
  the editor.
• 1.3 Save dataset

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Inputting data

• 2. Use of input command
• 2.1 input hhcode pid age
• 2.2 enter values of variables
• 2.3 end
• 2.4 Save dataset

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Inputting data

• NOTE
• We can copy and paste values from a spreadsheet
• Data can be entered variable-by- variable or
  observation-by-observation
• When entering data variable-by-variable, use TAB
  for observation-by-observation use ENTER key
• Missing data code is a period .

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Inputting data

• NOTE
• Numerical values SHOULD NOT include commas else
  these are considered string.
• String variable values can be almost any
  combination of letters, numbers, symbols up to 80
  characters long in Intercooled/ Small and up to
  244 characters in STATA/SE.

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Summary of STATA session
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Summary

• Stata Files
• .log records commands and outputs
• .do contains a sequence of Stata
  commands for batch execution
• .dta data files
• .graph graphics files
• .ado for writing new commands

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Summary

• Basic Commands
• Interrupt Stata Ctrl Break or Stop button
• Exit from Stata type exit or from File menu,
  choose exit or clear
• Help
• Search

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Summary

• To inspect datasets
• codebook display contents of variables
• count counts cases
• describe display properties of variables
• summarize descriptive stats
• list show values
• tabulate one or two way freq tables
• table higher dim freq tables
• tabstat tables with statistics
• Note weigh is important!!!!

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Summary

• To create and change varaibles
• generate/egen create new variable
• replace replace old values
• recode change values by conditions
• label label var (up to 80 chars)

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Summary

• To reorganize datasets
• rename change the name of a variable
• drop eliminate variables or observations
• keep keep variables or observations
• clone copy of an existing variable
• sort arrange into ascending order
• gsort arrange in ascending or descending order

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Summary

• To reorganize datasets
• append append two datasets
• merge merges two datasets
• reshape converts dataset from wide to long and vs

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Summary

• Survey Data Analysis
• svy commands
• svyset
• svymean
• svytotal
• svytab
• syyprop
• svyreg

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Summary

• Importing Datasets
• Files must be in text delimited form (.txt)
• Use infile function to import
• infile var1 var2 etc using filename.txt, clear
• Or the infix or insheet functions
• Or use StataTransfer software

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Please perform EXERCISE 4