CHAPTER III. DISCUSSION OF THE RESULTS Statistical Study The statistical study compared two groups of cases in respect to I.Q. These groups were selected from one large group, on the basis of presence or absence of tonsillar defect. The tonsil group was composed of 236 cases, and the normal group, of 294. The distribution of the two groups according to intelligence is set forth in Table I, and in Figs. I and II. TABLE I Tonsil Group Normal Group I.Q. No. of Per cent of No. of Per cent of Cases Cases Cases Cases 40- 50 2 .8 0 0 50- 60 1 .4 2 .7 60- 70 7 2.9 4 1.4 70- 80 21 8.9 29 9.8 80- 90 45 19.0 52 17.7 90-100 80 33.9 107 36.4 100-110 55 23.3 67 22.8 110-120 17 7.2 24 8.1 120-130 6 2.5 9 3.0 130-140 2 .8 0 0 140-150 1 .4 0 0 Average 94.9 95.4 Median 95.3 95.6 Q 8.705 8.27 [Sigma] 14.4 12.2 From these it is evident that the two groups are practically equal in intelligence. The average I.Q. for the normal group is 95.4, as compared with 94.9 for the tonsil group. The medians are equally close,--95.6 in the normal group and 95.3 with the tonsil cases. The difference in variability is negligible, Q being 8.705 and [Sigma] 14.4 in the tonsil group, while in the normal Q is 8.27 and [Sigma] 12.2. The two cases with the lowest I.Q.'s were tonsil cases, but the three highest I.Q.'s also belong in this group. Fig. 1. Distribution of I.Q.'s. Number of cases. Fig. 2. Distribution of I.Q.'s by percentage of total number of cases in the group. If the frequencies are expressed in terms of per cent of the total number of cases in the group, the two may be compared further. The following details are noticeable. I.Q. Per cent of Per Cent of Tonsil Group Normal Group Below 70 4.1 2.1 Below 90 32.0 29.6 Above 110 10.9 11.1 Above 120 3.7 3.0 Above 130 1.2 0