Data for: Model-free variable screening approaches with non-ignorable missing response
The resting-state functional magnetic resonance imaging data is from the Autism Brain Imaging Data Exchange study. The primary goal of this study was to understand how brain activity is associated with autism spectrum disorder, a disease with substantial heterogeneities among chlidren. Functional magnetic resonance imaging measures blood oxygen levels linked to neural activity, and resting-state functional magnetic resonance imaging measures brain activity only when the brain is not performing any tasks. This study aggregated 20 resting-state functional magnetic resonance imaging datasets from 17 experiment sites. For each subject, the resting-state functional magnetic resonance imaging signal was recorded for each voxel in the brain over multiple time-points. Standard imaging pre-processing steps (Di Martino et al., 2014) included motion correction, slice-timing correction, and spatial smoothing. The entire brain was registered into the 3mm standard Montreal Neurological Institute space, which consists of 38 547 voxels in 90 brain regions defined by the automated anatomical labelling system (Hervé et al., 2012). To select imaging biomarkers for study prediction, we considered the fractional amplitude of low-frequency fluctuations (Zou et al., 2008), defined as the ratio of the power spectrum for frequencies 0·01–0·08 Hz to the entire frequency range.