... 168 71 t-test 211 two-sample tests 204±8 experiment, Piagetian 90 experimental design 67 75 between-subject (independent) 74 ±5 ex post facto 70 laboratory and field 75 types 74 ±5 validity 87 90 ... errors 27, 81, 103, 160, 177 , 231 estimation 1 57, 160, 176 , 223 ethics 59, 70 , 74 , 232, 239±45 ethnography 52 ethnomethodology 8, 52 ethnoscience 52 evaluation of programmes 76 Everington, C 24±5 ... 87 interviews 72 , 85 7 introspective reports 230 intuition 37 inventory (test) 159 IQ tests 78 , 191±3 item scales, bias/error 81 J Walter Thomson (advertising company) 71 ±2 Johnstone, J.W.C 17 18...