The order of this section, and the one on editing (§ 7) are interchangeable. If you decide that you need to average your data (be it in frequency or time), you may need to edit it first. For example, there is no point to averaging in frequency if there is channel specific interference that would result in a corrupted averaged channel (such interference is not uncommon in the 13 and 20 cm bands). You would need to edit out the bad data first. Therefore, I suggest you read this section, and the section on editing first, and then proceed with whatever suits your needs.