Which electrode site is located half the distance between Fp2 and C4?

The correct choice is F4 because it is located at the appropriate position along the International 10-20 electrode placement system. Specifically, the electrode site F4 is situated halfway between the frontopolar site Fp2 and the central site C4, aligning with the standard measurements used in electroencephalography (EEG) and related practices.

This measurement is crucial for maintaining consistency in electrode placement, which directly impacts the quality and accuracy of the recorded data. The precise positioning aids in the effective monitoring of brain activity in different areas, ensuring that the data collected is representative of the intended regions of interest. In this case, placing F4 between Fp2 and C4 allows for optimal readings of brain activities that may occur in that transitional region between frontal and central lobe activity.