Table 3.

Results of Testing the Statistical Null Hypothesis β _T = β _R Using Welch’s t Test for Samples With Unequal Variances

Study	Schippling et al.		Vinke et al.
Ages	[40, 70] y		[45, 70] y		[70, 95] y		[45, 95] y
Sex	t	df	t	df	t	df	t	df
M	−56.99	3961
F	−81.90	4489
M and F	−75.47	3388	−60.89	1477	−424.05	1516	−159.05	1469

Notes: The number of degrees of freedom (df) was approximated using the Welch–Satterthwaite equation. Results are reported separately for males (M), females (F) and for combined samples including both males and females (M and F). The null hypothesis was tested for the Tsimane against the samples of both Schippling et al. (28) as well as Vinke et al. (29). In the latter case, the null hypothesis could only be tested for the combined samples of males and females (M and F) because Vinke et al. did not state the numbers of males and females in their sample. Furthermore, because the trajectories of Vinke et al. differ substantially across the age intervals [45, 70] and [70, 95] y, the null hypothesis was tested separately within each of these intervals. In all cases, the threshold for statistical significance is α = 0.05. All tests have p values <1.0 × 10^–200 and power >99%.