Table 8.

Comparing left and right hemispheres across spindle features

	$\beta$ original	t original	$\beta$ rankit	t rankit
Density (min−1)	−0.139	−0.73	−0.056	−0.504
Amplitude (µV)	−5.95	−0.633	−0.18	−0.348
Frequency (Hz)	−0.003	−0.046	−0.075	−0.638
Interspindle SD (Hz)	−0.017	−0.808	−0.09	−0.72
Intraspindle SD (Hz)	0.024	1.199	0.113	0.949
Frequency range (Hz)	0.051	0.973	0.088	0.732
Frequency change (Hz/s)	0.039	0.659	0.084	0.681
Duration (s)	−0.013	−2.374	−0.186	−1.645
Rise-decay symmetry	−0.001	−0.365	−0.045	−0.342
Peak-trough symmetry	−0.004	−1.517	−0.23	−1.694

The first two columns correspond to the estimated difference in a LMEM for each spindle measure between left and right hemisphere and the significance of this estimate (right hemisphere is reference). The next two columns represent the difference after rank inverse normal transformation (rankit) of the data. An asterisk indicates significance after correction for multiple comparisons (FDR, p < 0.05). Applying the rankit transformation did not change the significance of results, and no hemispheric differences survived correction for multiple comparisons. The $\beta$ estimates in column 1 are in natural units whereas the estimates in column 3 are normalized. QQ plots before and after transformation are shown in Extended Data Table 8-1.