Table 3.

Summary Statistics for Frailty Index Scores for Younger and Older Rats

	Younger rats		Older rats
	6 Months	9 Months	13 Months	17 Months	21 Months	Terminal
N	12	12	36	33	23	18
Mean FI score	0.03 ± 0.01	0.04 ± 0.01	0.06 ± 0.00	0.13 ± 0.01	0.21 ± 0.01	0.31 ± 0.02
FI score range	0.00–0.11	0.00–0.11	0.02–0.11	0.04–0.30	0.11–0.35	0.19–0.40
99th Percentile of FI score	0.11	0.11	0.11	0.28	0.34	0.40

Abbreviation: FI, frailty index.