void Main()
{
  DataTable dt=new DataTable();
  dt.Columns.Add("value",typeof(double));
  dt.Columns.Add("time",typeof(string));
  dt.Rows.Add(25.2,"2011-05-15 19:50:12");
  dt.Rows.Add(23.6,"2011-05-15 19:50:58");
  dt.Rows.Add(25.8,"2011-05-15 19:51:23");
  dt.Rows.Add(24.5,"2011-05-15 19:51:51");
  
  var max=dt.AsEnumerable().OrderByDescending(r=>r.Field<double>("value")).FirstOrDefault();
  
  var min=dt.AsEnumerable().OrderBy(r=>r.Field<double>("value")).FirstOrDefault();
  
  var average=dt.AsEnumerable().Average(r=>r.Field<double>("value"));
  
   
}