Table 1.

Actigraphy signal tests.

Property Test	Observations
Visual inspection	Spiky data with a lot of transient information randomly distributed. Motion events seem uncorrelated when separated by significant time period.
Stationarity—KPSS test [33]	Non-stationary signals
Linearity—Augmented Dickey–Fuller test [34]	Non-linear data
Gaussianity—KS test [35]	Non-Gaussian distribution in most cases, since human motion is random.
Sparsity test—Gini Index [36]	Sparse in short windows. In case of tri-axial data, vector compounding and additional quantization may be needed.