Thank you Jamie for today mornings message. I was confused by the complex syntax of American date selection
This solution was also obtained over the week end while working on a Fedora Linux machine on which Epidata entry and Analysis latest versions were installed..
Simple formulas, which produced wonders, are given below;
define interval ### let interval=wdate - dbirth *calculate the interval in days using American dates.
define interval ### let interval=(wdate dbirth)30.44 results in a error Data type mismatch
define interval ###.# let interval=(wdate dbirth)/30.44 calculates the interval months using American dates.
Epi Analysis accepts float type variables as suggested by Gillis Delmas. However round or integer prefix do not help. The output is produced in decimals and not rounded to the nearest figure.
I wanted to obtain the current age hence did not include this formula in Epidata Entry as suggested by Pedro Emmanuel Brasil
One request to Jens; Such examples should be included in the help file in the form of simple FAQs, which can save hours or even days of Epi Analysis Users (beginner and even experienced!!).
Thank you friends for your timely help Much appreciated
Dr. Shavinder Singh