Shareware Overload Trio 2

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Text File | 1994-08-22 | 16KB | 463 lines

******************************************************** * * * TUTOR2.PGM * * * ******************************************************** set pause=off cls echo echo echo echo echo echo echo This Tutorial continues the instruction in ANALYSIS begun echo in the TUTOR1.PGM program. echo echo It provides an introduction to some of the topics in echo Chapter 11 of the Epi Info manual. echo ?Press <Enter> to continue (<F10> to QUIT): ? cls echo echo echo echo echo You can learn from this tutorial how to: echo echo Run DOS commands from ANALYSIS echo BROWSE through or UPDATE data files echo Control the treatment of missing values echo Use the SELECT, DEFINE, RECODE, and IF commands echo Manage dates and calculate intervals echo SET formatting options echo Save commands as programs echo echo echo ?Press <Enter> to continue (<F10> to QUIT): ? cls echo echo echo echo echo Let's begin by making a copy of the OSWEGO.REC file echo so that we can alter it without changing the original. echo echo The DOS command lets you use DOS commands, such as COPY echo or even run other programs like EPED. echo echo echo Please type: DOS COPY OSWEGO.REC OSWEGO2.REC echo ?EPI> ? CLS echo echo echo echo echo echo echo Now type: READ Oswego2 echo echo echo (You can use either upper or lower case for commands.) echo echo ?EPI> ? CLS echo echo echo echo echo echo In the tutorial we will do some analysis of echo cases in the OSWEGO2 file. To select cases only, echo echo echo Type: SELECT ILL = "Y" echo echo (Be sure it is a capital "Y"; the rest can be upper or lower case.) ?EPI> ? CLS echo echo echo echo The BROWSE command lets you look at the data file in echo spreadsheet format. You can move around with the echo arrow keys and see all the data, but, for safety's echo sake, cannot change the values. echo echo To BROWSE, press the <F4> key or type BROWSE echo echo When you see the data, move around and verify that echo you can see the whole file. Try out the prompts echo at the bottom. When you have finished, press <F10>. echo ?EPI> ? ?Press <Enter> to continue (<F10> to QUIT): ? cls echo echo echo echo echo UPDATE is just like BROWSE, except that you can change echo the data items. This is the only command in echo ANALYSIS that actually changes the original echo data file; it is important to make a backup file, echo as we have already done, before using UPDATE. ?Press <Enter> to continue (<F10> to QUIT): ? cls echo echo To use UPDATE, simply type UPDATE. You will see the same echo "spreadsheet" you used in BROWSE, but now changes can echo be entered in the space at the top. Your entry will appear echo at the location of the cursor bar in the data area. echo echo Type UPDATE and change the blank values for TIMESUPPER echo to 2000, the approximate mean of the others. Times like echo "1930" mean 19 hours and 30 minutes. Change them to echo 1950, since we will later divide by 100 to get times echo in hours. Do this for both TIMESUPPER and ONSETTIME. ?EPI> ? ?Press <Enter> to continue (<F10> to QUIT): ? cls echo echo echo echo echo In subsequent operations, we want ANALYSIS to echo exclude missing values from the calculations and tables. echo Normally, they are included, and are treated echo as zeroes. This can be changed with the SET echo command. echo echo echo echo echo Type: SET IGNORE = ON ?EPI> ? echo cls echo echo echo echo You have probably noticed that TIMESUPPER and echo ONSETTIME are in military time, but that the echo date for TIMESUPPER when the offending meal echo was eaten is not in the data file, since in echo all cases it was 04/18. echo echo We will now proceed through the several steps echo necessary to calculate an incubation echo period for each case. echo ?Press <Enter> to continue (<F10> to QUIT): ? cls echo echo echo echo First we will DEFINE a new variable, since we echo need a place to store the result of the echo calculation. Let's call it INCUBATION, echo since variables can have names of up to 10 letters. echo We will make it a numeric variable with one echo decimal place, since the incubation will be echo in hours, to the nearest half hour. echo echo echo Type: DEFINE INCUBATION ##.# echo ?EPI> ? ?Press <Enter> to continue (<F10> to QUIT): ? cls echo echo echo echo echo We would like to convert both ONSETTIME and TIMESUPPER echo to an absolute number of hours with a defined starting point echo so that we can subtract TIMESUPPER from ONSETTIME to get echo INCUBATION in hours. echo Arbitrarily we choose the first instant of 04/18 as the echo reference point at which to start the clock. echo ?Press <Enter> to continue (<F10> to QUIT): ? cls echo echo echo echo echo Since all TIMESUPPERs were on 04/18, we do not need echo to adjust the hour of onset if ONSETDATE was 04/18. echo For cases with ONSETDATE on 04/19, we can use echo the IF command to adjust ONSETTIME by adding 2400 echo hours if ONSETDATE was 04/19. echo echo echo Type: IF ONSETDATE = "04/19" THEN ONSETTIME = ONSETTIME + 2400 echo echo (Note that values for dates must be in quotation marks.) ?EPI> ? ?Press <Enter> to continue (<F10> to QUIT): ? cls echo echo echo echo echo Now we are ready to calculate INCUBATION. echo echo Type: INCUBATION = (ONSETTIME - TIMESUPPER)/100 echo ?EPI> ? cls echo echo echo echo To assess the results, echo echo Type: FREQ INCUBATION ?EPI> ? ?Press <Enter> to continue (<F10> to QUIT): ? cls echo echo echo echo echo Now type: BAR INCUBATION ?EPI> ? cls echo echo echo echo echo We hope the results are reasonable for a staphylococcal echo food poisoning outbreak. If not, perhaps you typed echo one of the commands wrong, but, in any case, you echo have seen how mathematical expressions and IF echo statements work in ANALYSIS. echo echo ?Press <Enter> to continue (<F10> to QUIT): ? cls echo echo echo echo echo The next task is to group the AGEs so that they echo can be handled more easily. echo echo This is a job for the RECODE command. ?Press <Enter> to continue (<F10> to QUIT): ? cls echo echo echo First we need another variable to receive the echo results; let's call it AGEGROUP. It will be echo a text or "string" variable since the groups echo will be items like "0 to 20" which are not echo entirely numeric. echo echo Type: DEFINE AGEGROUP __________ echo echo (AGEGROUP is followed by 10 underline characters, just echo as though we were creating a questionnaire variable.) echo ?EPI> ? cls echo echo echo RECODE always recodes a known variable like echo AGE to a variable (sometimes the same one) echo like AGEGROUP. Since AGE is numeric, and echo we want new values containing text, echo we had to create the text variable AGEGROUP echo to receive the results. echo echo Type: echo echo RECODE AGE to AGEGROUP 0-19="0 to 19" 20-39="20 to 39" 40-59="40 to 59" echo echo ?EPI> ? cls echo echo echo The older group didn't fit on the same line, and, since RECODE's echo are cumulative, we can include this group in another statement. echo In a program file, to be described later, you can type lines echo longer than 80 characters or use "\" to continue a line, echo but, for now: echo echo Type: RECODE AGE to AGEGROUP 60-HI=">=60" echo echo ("HI" is an expression for the highest value.) ?EPI> ? echo cls echo echo echo echo To test the hypothesis that INCUBATION and AGEGROUP echo are associated (and that you typed in all the echo commands correctly), echo echo Type: TABLES AGEGROUP INCUBATION echo ?EPI> ? echo ?Press <Enter> to continue (<F10> to QUIT): ? cls echo echo echo echo Another way to look at a possible association would echo be to make a scatter graph of AGE and INCUBATION echo since both are numeric variables. A echo least squares regression line will be echo useful here, so we end the command with "/R". echo echo Type: SCATTER AGE INCUBATION /R echo ?EPI> ? cls echo echo Dates are complex and should be studied in chapter 11 of the echo manual, but we will do a simple subtraction to give the echo general idea. The OSWEGO data set has only two dates, echo 04/18 and 04/19, but these will do for practice. echo echo Let's pretend that we want an incubation echo period in days and that it will be obtained echo from subtracting 04/18 from ONSETDATE. echo echo Type: Incubation = ONSETDATE - "04/18" echo echo The result will be in DAYS and the literal value "04/18" must be echo in quotation marks since dates are a special form of text variable. ?EPI> ? cls echo echo echo echo The INCUBATIONS should all be 0 or 1 days, which echo of course, is not very useful here, but echo would be appropriate for diseases with echo longer incubation periods. echo echo echo Type: LIST ONSETDATE INCUBATION ?EPI> ? echo ?Press <Enter> to continue (<F10> to QUIT): ? cls echo echo echo echo echo The SET command allows setting many options that echo affect the appearance or the printing of tables. echo echo Press the <F1> key and choose the section of echo the help file that describes the SET commands. echo Read about the possible settings and then echo press escape to continue with the tutorial. echo ?Press <Enter> to continue (<F10> to QUIT): ? cls echo echo echo echo echo echo echo echo Type: SET PERCENTS = ON echo ?EPI> ? ?Press <Enter> to continue (<F10> to QUIT): ? cls echo echo echo echo echo echo Each cell in the table will now contain percentages. echo Those with the right arrow ">" are percentages of echo the totals on the right; the others have the echo totals at the bottom for denominators. echo echo Type: TABLES AGE SEX ?EPI> ? ?Press <Enter> to continue (<F10> to QUIT): ? cls echo echo echo echo echo SET commands and others can be preserved in echo a program file with the special name echo CONFIG.EPI so that they take effect echo automatically each time ANALYSIS echo is run. More details are given echo in the Epi Info manual. echo ?Press <Enter> to continue (<F10> to QUIT): ? cls echo echo echo echo echo echo Our final topic is PROGRAM files. A program is echo merely a series of Epi Info commands saved in echo a text file. You can create a program in EPED echo by typing one command on each line and then echo saving the file with a name ending in .PGM, such echo as OUTBREAK.PGM. To run the program in ANALYSIS echo you would use the command RUN OUTBREAK. echo ?Press <Enter> to continue (<F10> to QUIT): ? cls echo echo echo echo If you have already typed several commands from echo the keyboard in ANALYSIS and want to save them echo in a program file, the SAVE command will put echo up to 20 previous commands in a file. You would echo type SAVE followed by the filename, such as echo CLEANUP.PGM, and the program file will be created echo automatically. You could then use EPED to echo edit and embellish the program before echo RUNning it in ANALYSIS. echo ?Press <Enter> to continue (<F10> to QUIT): ? cls echo echo echo echo This completes the TUTOR2 tutorial. echo You have learned to: echo echo Run DOS commands from ANALYSIS echo BROWSE through or UPDATE data files echo Control the treatment of missing values echo Use the SELECT, DEFINE, RECODE, and IF commands echo Manage dates and calculate intervals echo SET formatting options echo Save commands as programs ?Press <Enter> to continue (<F10> to QUIT): ? cls echo echo echo echo The way to learn more is to write programs echo to analyze your own data. echo Try to start with the simple operations echo first and work up to the more complex. echo echo Good luck. We hope you enjoy using Epi Info. ?Press <Enter> to leave the tutorial: ?