Introduction to Epi Info.pdf

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1. Introduction to Epi Info
Emiru Merdassa
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2. 2
–Overview of EPI-Info
–Data entry using EPI-INFO
–Sample size determination
Outline
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3. 3
•Epi Info is a public domain database and statistics program.
–Develop an electronic data entry form
–Customize the data entry process
–Enter data, and analyze the data
–Statistics, graphs, tables, and maps can be produced with simple commands
–Epi Info is free, downloadable software provided by the CDC
(www.cdc.gov/epiinfo)
Introduction
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4. 4
•Make view
–For designing an electronic data entry form which automatically creates
a data table.
•Enter data
–For entering data into the designed electronic data entry form.
•Analyze Data
–For conducting a relatively wide range of statistical analysis of the data.
Main applications in Epi Info
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5. The Epi-Info 7 Main Menu
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6. Epi Info –Core Principles
–Free
–Easy to use
–Flexible
–Standards based
–No “IT guys” needed in most cases
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7. Designing a Form
❑The Form Designer has several “work areas”
▪The Menu
–The toolbarcontains buttons for creating projects, editing the form’s check code,
going to the data entry module, and undo/redo.
▪The Project Explorer is where you can add and remove forms from your project,
add, edit, and remove pages from individual forms, and work with templates.
▪The Canvasis where fields are placed, moved, and edited.

8. Designing a Form
1.The Menu
2.The Project Explorer
3.The Canvas

9. Creatingquestion/prompt
Choice one
ofthe
propertyfor
thevariable
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10. Sample Size determination using Epi Info
•Step 1: Go to the main menu at the top left corner and click on StatCalcand subsequent
options
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11. Sample size determination
•Fillthecomponentsnecessarytodeterminesamplesizeforthethreecasescenarios:
Populationsurvey,Unmatchedcasecontrol,andCross-sectionalorCohortstudy
designs.
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12. Exercise
Letusassumethepopulationthatwewanttoconductthestudyhasatarget
populationofsizeN=100,000,andtheproportionofthevariableofinterestisnot
knownwhichmeansthereisnopreviousstudydoneandhencewedecidedtouse50
percentasanestimateoftheprevalenceforthatvariable.
a)Whatwouldbethesamplesizerequiredifthesamplingtechniquewassimple
randomsampling?
b)Whatwillbethesamplesizeifthesamplingtechniqueistwostagesampling
andisalsoexpectedtohave10%non-responserate?
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13. Exercise
•Theprevalenceofunderweightofnewbornsiscomparedbetweentwo
regions.Inoneregion,itisestimatedthatabout30%ofthemcouldbeunder
weight.Inotherregionitisprobably15%.Iftherequiredsampleistoshow
witha90%likelihood(power)thatthepercentageofnewbornsisdifferentin
thesetworegionsat95%confidencelevel,whatwouldbethesamplesize?
Supposethatthecurrentstudyusesmultistagesamplingandanothersimilar
studyhasreported91.5%responserate.
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14. Thank you
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