Cathy, it appears to me that your example question really doesn't ask for a "number" from the student but a "string representation of a number". If I were setting up such an as_item, I'd set the data_type as varchar and then set an as_item_check to specify the user response to be "string eq $user_response $correct_answer" (or something like that -- we haven't actually worked this out yet). I wouldn't even handle this situation as a real number since the point of the question is whether the student types in the correct number of significant digits and order of magnitude in the right format.
In contrast, for data-driven apps like I need, the point is to collect various kinds of numbers upon which we can do various kinds of statistics. Of course, all that can be done in SPSS or SAS once a bulk data extraction is accomplished, but eventually it would be great to build in R via PG so that lots of cool analytic and graphing stuff can be done within the Assessment package. If we munge everything that Assessment collects into strings, then this becomes impossible. And in the near term, the ability to be able to do means, stddevs, and other simple descriptive statistics on the fly is an absolute requirement for the Assessment package. For me anyway. 😉
