Dissertation - Michael Becker

a few participants in the middle. The “surface” group is characterized by a large numberof participants at the higher end of the scale, while the participants in the “deep” group aremore heavily concentrated at the low end.(123)14no. of participants12108642DeepSurface00-2 3-5 6-8 9-11 12-14 15-17 18-20generalization scoreSince statistical tests that assume a normal distribution, such as the t-test, are out, thedata was transformed using a cut-off point. Participants who scored above the cut-off pointwere given a score of 1, and the others were given a score of 0. The transformed resultswere compared with Fisher’s exact test. At a cut-off point of 17, the difference betweenthe groups is significant (odds ratio 3.736, p = .047). The choice of 17 for the cut-off pointcomes from the distribution of the generalization scores in the “surface” group, where noparticipant scored in the 13–17 range, inclusive, suggesting that a score of 18 or above isthe minimum for being considered a good generalizer.The by-item analysis also shows a significant difference in the performance of the twogroups. The chart in (124) shows the number of participants who successfully changeda stem vowel [i] in the singular to [o] in the plural and vice versa for each item, andthe number of participants who successfully changed the stem vowel and also chose theexpected plural affix for the language they learned. The differences between the groups aresignificant both for the stem vowel change only (paired t-test: t(19) = 7.36, p < .001) and123