(a) (b) (c) 1-20 21-40 41-60 a+b all A 6 3 6 12 15 C 4 7 7 11 18 G 6 6 3 9 15 T 4 4 4 8 12 18! 15! 15! 12! 3! 7! 6! 4! 3! 3! 12! 11! 9! 8! 3! ------------------ v. -------------- . ---------------- 63! 23! 43! take neg logs: null v. GC-rich "red" ----- ------------- 201.0 (63) 121.5 (43) - 36.4 (18) + 51.6 (23) - 27.9 (15) - 20.0 (12) - 27.9 (15) - 17.5 (11) - 20.0 (12) - 12.8 (9) - 1.8 (3) - 10.6 (8) ------ - 8.5 (7) 87.0 nits * - 6.6 (6) - 3.2 (4) - 1.8 (3) - 1.8 (3) - 1.8 (3) ------- 88.5 nits
Answer: the null wins by a small margin (odds about 4:1)
Please [check]!
(And note that if the supposed cut points (20+ & 40+) were not "common knowledge" but had to be stated in the hypothesis, that would add about 8 nits more to the "red" hypothesis.)