how often should an event be repeated when can you use a sensitive instrument to record an event how many times does an n test need to be repeated what is an unacceptable n how many times should an event happen per subject what is the n for exposing a subject to an unusual event how many times should brain activity occur when is an n acceptable what is the n of experiments at what n number is an n acceptable how many times can a brain event be recorded? how many times expose subject to stimulus under what circumstances is an n  30 acceptable how often is it useful to record an event how many times is an n acceptable how many times is a stimulus acceptable how many times should a stimulus be exposure what is the n-value of unusual stimulus what is the n of a normal stimulus how many times to expose to unexpected stimulus