First of all, for all of you wrestling with the thorny problem of whether to join the church of Steve and get an iPhone or join Ms. Palin in going rogue by plumping for a Droid, check out the xkcd comic strip on the topic. Brilliant!
Anyway, it seems the problem I posed in a recent column about how to get an Excel spreadsheet to randomize the numbers from 1 to 75 is still generating comments.
In response to the final and most elegant solution that I discussed a couple of weeks ago , one reader noted that should two identical random values be generated the spreadsheet will fail and, indeed, that is correct except it shouldn't happen.
Remember that the random number generator in Excel is actually a pseudo-random generator. The formula it uses creates a sequence of values to 15 decimal places that, according to Microsoft , doesn't repeat for at least 10^13 generated values. Given that we're using 75 values per recalculation of the spreadsheet, if we did a recalc once per second it would take something like 42,280 years before we'd get a repeat. I'd hazard that's good enough for everyday purposes.