Table 4:

Sample sizes necessary to detect the observed longitudinal racial differences (i.e., the annual rates of change) in a future longitudinal study (6 years follow-up with assessments every 2 years, 1:1 or 1:2 sample size ratio assumed between AAs and Whites)

Marker	Observed slope difference (AA-White)	Variance for the random slope	Variance for the random error	AAs needed for a 1:1 design	AAs needed for a 1:2 design
CSF Aβ42	14.2275	16	130	128	96
CSF Aβ42/Aβ40	0.0004964	0.0008743	0.0055696	220	165
Amyloid PET centiloid	−0.7624	1.546	7.095	198	148
CSF Tau	−4.876	17.22	47.28	402	301
CSF pTau181	−0.5122	1.633	6.488	425	319