Which frequency cannot be calculated for in a high-frequency average?

In audiometric testing, the high-frequency average is typically calculated using frequencies that are specifically recognized in the assessment of hearing loss, particularly in the higher ranges. The high-frequency average often encompasses frequencies such as 1 kHz, 1.5 kHz, and 2 kHz, as these fall within a commonly accepted range for high-frequency testing.

However, the frequency of 3 kHz is often considered too high to be included in a high-frequency average calculation in many clinical contexts. Audiological practices sometimes define the high-frequency average based on a specific subset of frequencies, typically not extending to 3 kHz, as this frequency is generally categorized as part of the very high frequencies. Consequently, the calculation for a high-frequency average excludes 3 kHz since it does not align with the standard frequencies considered in this average.

Thus, the correct choice, representing the frequency that cannot be calculated for in a high-frequency average, is 3 kHz.