Strangely enough, decrease in fatigueability as described in the previous chapter does not show itself after 12 months. In fact, the negligible loss in ability noticeable after six months has increased after a period of twelve months. In only 4 out of 11 test group cases, is the gain in the second period equal to that of the first, a similar result to that found in the control group, where 5 out of the 11 cases made half their total gain in the second interval. The results are compared below. 6 months 12 months Average of gains of test group in excess of control -.020 - .06 Median of gains of test group in excess of control -.015 - .09 P. E. of difference +-.04 +- .036 Average in terms of P. E. -.50 -1.66 Median in terms of P. E. -.38 -2.50 TABLE XX Tapping for Fatigue, Second Retests, 11 Pairs N[16] Test Group (A) Control Group (B) Test 1 Test 3 Gain Test 1 Test 3 Gain A-B 20 -.10 .03 -.13 .20 .0 .20 -.33 27 .15 .17 -.02 .09 -.17 .26 -.28 10 -.09 .27 -.36 .06 .16 -.10 -.26 14 .09 .05 .04 .13 -.13 .26 -.22 13 -.03 -.06 .03 .27 .07 .20 -.17 28 .01 .05 -.04 .17 .10 .07 -.11 15 .03 .03 .0 .18 .08 .10 -.10 23 .11 .0 .11 .06 .0 .06 .05 21 .27 -.01 .28 .29 .14 .15 .13 11 .28 -.04 .32 .11 -.01 .12 .20 18 .14 -.15 .29 .01 .15 -.14 .43 Av. .078 .031 .047 .143 .035 .107 -.06 M .03 .12 -.09 75%ile .153 .20 .07 25%ile -.062 .02 -.275 Q .107 .09 .172 P. E. (distribution) .087 .093 .19 P. E. (average) +-.02 +-.03 +-.036 Av.=-1.66 P. E. M.=-2.50 P. E. The point of greatest interest in the present study is, as has been said, improvement in intelligence. Does operation for adenoids and tonsils result in improvement in intelligence, as measured by I.Q.? If such improvement does not manifest itself after six months, can it be found after a second period of the same length? The latter question is answered by observation of Table XXI and attention to the following facts, gathered from the 21 pairs of cases who were given intelligence tests after the twelve months' interval.