Table 2:

Power analysis and sample size calculations. The top set of comparisons reflects group sizes for main effects of age or sex as analyzed throughout the manuscript. Bottom rows reflect analysis of sex differences separated by age group. * indicates a significant main effect was found in the parent ANOVA for the corresponding variable. While swim velocity and spatial learning index (SLI) may be underpowered for rejecting the null hypothesis that aged rats are impaired relative to young, based on power analyses, unreasonable group sizes may be required to detect a potential sex difference based on the effect sizes observed in the current data.. Furthermore, working memory biconditional association task (WMBAT) performance is unlikely to be a type II error when comparing all males and females, or when comparing the two sexes in individual age groups.

	Power	Required Sample Size	Power	Required Sample Size	Actual Sample Size
Task	All young vs all aged subjects		All male vs all female subjects
Grip strength (normalized)	0.37*	30	0.99*	5	10
Rotarod Latency	0.79*	7	1*	2	6
Rotarod Speed	0.94*	7	1*	2	6
Swim Velocity	0.31	38	0.13	109	10
SLI	0.46	23	0.06	508	10
WMBAT Day 10	0.96*	6	0.12	126	10
Incorrect trials to criterion	0.93*	7	0.09	218	10
	Young male vs young female		Aged male vs aged female
Grip strength (normalized)	0.7	7	0.83	5	5
Rotarod Latency	1	1	0.75	4	3
Rotarod Speed	1	1	0.99	3	3
Swim Velocity	0.33	17	0.03	2003	5
SLI	0.05	388	0.05	504	5
WMBAT Day 10	0.2	33	0.04	720	5
Incorrect trials to criterion	0.05	396	0.14	51	5