hello everybody, I have collected ERP from 21 adults ; sound onset and acoustic change evoked N1-P2 peak to peak amplitudes and N1 peak latencies were compared between 3 conditions (quite, +10 dB and 0 dB SNR). for onset responses amplitude and latency of N1 was compared between these 3 conditions with paired samples t-test, for acoustic change response only quite and +10 dB SNR was compared with t-test also. more over I calculated the difference scores (amplitude decrements for amplitudes and latency prolongation for latencies) for acoustic change and onset between quite and +10 dB SNR, and compare these with independent t tests.

I was asked to use bonferroni correction, can some one help me? I am planning to divide p .05 with 3 for onset responses, and 2 for acoustic change responses and take them as a new p value? do I need a correction also for comparing difference scores?