Transcript Mod6Part2

Epi Info™ 7 Training
Software for Public Health
Course Title: Using Epi Info™ 7
Using Classic Analysis (Continuation)
April 17 2012
Office of Surveillance, Epidemiology, and Laboratory Services
Epidemiology and Analysis Program Office
Module 6 – Part II Outline
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Basic Analysis Statistics PowerPoint Slide Presentation
Instructor demonstration Analysis, Creating Statistics
Students practice
End of Lesson Questions
Classic Analysis – Creating Statistics
 Interested in discovering from the
data?
 The frequency of Ill cases
 What is the average age for cases who got ill?
 Is there a strong relationship between ill cases
and a specific food item that was consumed?
Classic Analysis Commands
 DISPLAY
 SET
 FREQUENCIES
 MEANS
 TABLES
Creating Statistics
 Use the FREQUENCY command to discover the
distribution of the population based on geneal
demographic information.
 Use the TABLES command to discover the odds
and risk ratios for foods eaten.
 Use the MEANS command to find out average age
of cases.
DISPLAY command
 The DISPLAY command allows the display of
metadata information about tables, forms, and
database information.
DISPLAY output
SET command
 The SET command provides various options
that affect the performance and output of data
in Classic Analysis.
 These settings are utilized whenever the
Classic Analysis program is used.
 Some of these settings will be available in a
future Epi Info 7 release.
SET command
FREQuency command
 Produces a table showing how many records have
each value for the specified variable(s).
 A Weight variable is selected for use in weighted
analyses or when the current dataset consists of
summary data.
 Stratify By identifies the variable to be used to
stratify or group the frequency data.
 Output to Table field identifies a data table to
receive output from the command.
FREQ command
FREQ Died
MEANS command
 Used when variable of interest is numeric and measured
on a continuous scale.
Means Of identifies the variable whose mean is to be computed.
A Weight variable is selected for use in weighted analyses. The weight
variable applies to all aggregation clauses.
The Output to Table field identifies a data table to receive output from
the command.
The Cross-Tabulate by Value of variable is used to cross-classify data.
Stratify By identifies the variable to be used to stratify or group the means
data.
MEANS command
MEANS Age Sex
TABLES command
 Performs a cross-tabulation of the specified variables
In other words, it examines the relationship between
two or more categorical values.
 In this test scenario, you might want to know if there
is an association of consuming Strawberries or
Cooked Bacon with getting ill.
TABLES command
 A Weight variable is selected for use in weighted
analyses or when the current dataset consists of
summary data.
 Stratify By identifies the variable to be used to
stratify or group the data.
 Output to Table field identifies a data table to
receive output from the command.
TABLES command
TABLES Strawberries Ill
Glossary of Terms
 Odds Ratio – measure of effect size, describing the
strength or non-independence between two data
values.
 Risk Ratio – measure of a risk and if being exposed
to a factor increases the probability that an event
will occur
 P-Value - probability of observing the value of the
significance test (< 0.05 is often considered
“significant”)
 Confidence Interval - A range of values for a variable
that indicates the likely location of the true value of
a measure.
Saving an Epi Info™ Program
 In order to re-create the same statistics after data has
been added, you want to save the program or code.
 You can run these same statistics on the new records as
many times as possible.
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From the Program Editor, click File>Save Pgm. The Save
Program dialog box opens.
Click TEXT FILE option
Name Program as desired (i.e. Program1)
Save file in desired location.
Click Save
Click OK
Saving an Epi Info™ Program
Running a Saved Epi Info™ Program
 From the Program Editor, select File > Open Pgm or click the
Open Pgm icon. The Read Program dialog box opens.
 Click Text File to view all available .pgm files.
 Click OK. The program code opens in the Program Editor.
 Click Run Commands. The Program Editor runs all the code
listed and displays the results in the Output window.
 To run individual commands, use the cursor to highlight the commands
you want to run. Click Run Commands.
What Have You Learned!
 Use the DISPLAY command to view variable
types in your project.
 Use the FREQ command to see how your
data is distributed.
 Use the TABLES command to see if risk
factors are linked to outcomes.
What Have You Learned!
 Use the MEANS command to see if one
set of data is equal to the sum of the
data divided by the number of items in
the data set.
 Save Program (.PGM) files for use with
later data tables or updated data.
Questions?
For more information please contact Centers for Disease Control and Prevention
1600 Clifton Road NE, Atlanta, GA 30333
Telephone, 1-800-CDC-INFO (232-4636)/TTY: 1-888-232-6348
E-mail: [email protected]
Web: www.cdc.gov
The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of
the Centers for Disease Control and Prevention.
Office of Surveillance, Epidemiology, and Laboratory Services
Epidemiology and Analysis Program Office