13. The system of claim 12, further comprising a trend detector operable to determine whether said set of observations for each of said first plurality of queries contains trends.
13. The system of claim 12, further comprising a trend detector operable to determine whether said set of observations for each of said first plurality of queries contains trends. 16. The system of claim 13, wherein said trend detector is operable to add queries from said first plurality of queries having a trend at a predetermined significance level to a second plurality of queries.