Table 1. Probability of Membership in the Four Age/Muscle-Type Groups for Samples in the Validation Data Set.

Sample	Young Fast-Twitch	Old Fast-Twitch	Young Slow-Twitch	Old Slow-Twitch
Y1Fa	.173	0	0	0
Y2Fa	.058	1.08 × 10−22	3.90 × 10−31	5.56 × 10−29
Y3Fb	1.000	1.39 × 10−13	2.11 × 10−24	9.26 × 10−25
Y4Fc	.567	2.34 × 10−31	1.53 × 10−37	1.08 × 10−34
Y5Fc	.020	1.16 × 10−26	1.10 × 10−33	2.75 × 10−31
O1Fb	1.61 × 10−5	.384	2.66 × 10−17	1.06 × 10−17
O1Fc	.071	.837	7.07 × 10−19	5.02 × 10−18
03Fb	0	.555	1.68 × 10−21	2.80 × 10−19
04Fb	1.06 × 10−24	.424	1.74 × 10−31	3.40 × 10−25
06Fa	3.81 × 10−23	.063	0	1.01 × 10−36
Y1Sb	8.79 × 10−32	6.43 × 10−21	.655	4.42 × 10−13
Y2Sa	0	1.39 × 10−21	.005	4.69 × 10−11
Y4Sb	3.45 × 10−30	2.11 × 10−20	.158	2.57 × 10−5
Y4Sc	3.33 × 10−29	2.00 × 10−20	.143	2.41 × 10−6
Y6Sb	2.75 × 10−37	1.72 × 10−20	.764	.225
O1Sc	0	2.30 × 10−20	.001	.685
02Sa	0	4.56 × 10−24	3.79 × 10−28	.986
02Sc	0	2.32 × 10−21	0	.489
04Sb	0	2.12 × 10−21	.002	.414
05Sa	8.62 × 10−20	7.37 × 10−22	7.83 × 10−25	.037

Notes: The probability of membership values >.05 (95% confidence interval) are shown in boldface; values between .01 and .05 are shown in italics.

The number between the two letters identifies the animal; the last character is a notation describing the run number in the triplicate analysis. Example: 05Sa=old rat #5, slow-twitch muscle, run a).

YF = young fast-twitch; OF = old fast-twitch; YS = young slow-twitch; OS = old slow-twitch.