Hi, suppose we have a data in data.frame like a: data id q1 q2 q3 c 1 1 0 0 1 a 2 2 0 0 1 b 3 3 1 0 0 b 4 4 0 1 0 a I need from this data receive cross validation table like a a b <-- classified as 2 0 | a = a 1 1 | b = b Plus i need have information about 'id' i.e I need known what object I wrong classified. Suppose in (b,a) I need save object 'id'. In this example into (b,a) I need save only one id = 2 c(2). The object for id 2 will be class 'a' not 'b' for respone many thanks Best, Marcin M. -- View this message in context: http://r.789695.n4.nabble.com/Aggregate-data-and-table-function-tp3672339p3672339.html Sent from the R help mailing list archive at Nabble.com.