Table 4.

Representation of High Extinguishers (HEs) versus Low Extinguishers (LEs) in phenotypic subgroups. LE rats were strikingly over-represented in Subgroup 5; nearly one out of every two LE rats was characterized by severe, persistent fear, whereas only one out of 25 HE rats fitted this profile, an improbable difference (p < 0.01) under the null hypothesis. There was no evidence of over- or under-representation of HE or LE subjects in any of the other subgroups (p ≥ 0.21).

subgroup phenotype	LE	HE	p-value
1	0.00	0.14	0.61
2	0.32	0.32	1.00
3	0.09	0.04	0.99
4	0.14	0.36	0.21
5	0.41	0.04	0.01
6	0.05	0.04	1.00
7	0.00	0.07	0.97