Nao seja por isso...
structure(list(ID2 = c("Lorca M-1992", "Carvalho MR-1993", "Hamerschlak N-1997",
"Oeleman WMR-1998", "Cabalero ZC-2007", "Otani MM-2009", "Otani MM-2009",
"Remesar MC-2009", "Anes N-2010", "Flores Chaves M-2010"), VP = c(77,
224, 20, 515, 68, 167, 167, 340, 19, 66), VN = c(98, 182, 36,
481, 225, 257, 261, 1097, 15, 132), with = c(82, 224, 20, 539,
69, 168, 168, 356, 23, 66), without = c(98, 191, 40, 486, 238,
262, 262, 1099, 15, 157), group = c("ABBOTT-ABBOTT CHAGAS ELISA",
"ABBOTT-ABBOTT CHAGAS ELISA", "ABBOTT-ABBOTT CHAGAS ELISA", "ABBOTT-ABBOTT CHAGAS ELISA",
"BIOSCHILE-TEST ELISA CHAGAS", "ABBOTT-ABBOTT CHAGAS ELISA",
"BIOSCHILE-TEST ELISA CHAGAS", "BIOSCHILE-TEST ELISA CHAGAS",
"BIOSCHILE-TEST ELISA CHAGAS", "BIOSCHILE-TEST ELISA CHAGAS")), .Names = c("ID2",
"VP", "VN", "with", "without", "group"), row.names = c(50L, 42L,
69L, 60L, 37L, 113L, 111L, 124L, 97L, 102L), class = "data.frame")