2.8 Data Analysis
Single-participant averages were constructed by averaging all remaining trials following the rejection procedures outlined in Section 2.6. Grand-average waveforms were then generated for each participant group separately by averaging individual participant waveforms from within the group. Waveforms were compared between participant groups to assess neural differences in MRCPs as a function of clinical diagnosis.
For each participant, trials were sorted based on RT. To examine neural differences between slow and fast trials, each participant’s single-trial data were classified into one of four RT quartiles: fastest 25%, middle 25-50%, middle 50-75%, slowest 25%. Group average traces were constructed by averaging individual participant waveforms for each RT bin.
Age-related effects on MRCP morphology were examined by constructing group-average waveforms consisting of data from only participants falling within one of the following three age ranges, selected to achieve Ns of 20+ per age and clinical group: (1) 6-8.99 years [n=21 TD, n=27 ASD], (2) 9-11.99 years [n=26 TD, n=24 ASD], (3) 12-15 years [n=25 TD, n=21 ASD]. Participants older than 15 years of age were excluded from this analysis. Group average traces were constructed separately for ASD and TD groups.