How are dates represented in STATISTICA data files?
Date values of variables are internally stored in Julian format, that is, as a single integer value that represents the number of days that have passed since January 1, 1900; for example a date entered and displayed as 1/21/1968 will be stored as the Julian date 24858; the (optional) decimals are interpreted as time (see the next topic). Date values stored in this manner can be used in subsequent analyses (e.g., in Survival Analysis in order to calculate survival times, see below) and transformed using arithmetic operations; at the same time, they can be displayed as dates in reports or graphs (e.g., used to label scale values). Julian date values can be displayed in the spreadsheet in numeric (Julian) format or in one of several pre-defined date display formats (e.g., 1/6/64, 6-Jan-64, Jan-1964, 01/06/64, 01/06/1964, 6-Jan). To change the date display format, select the Date format option in the Current Specs dialog (accessible by double-clicking on the variable name in the spreadshee
