In a technical job interview I was asked a question that I couldn't quite make sense of. The interviewer was talking about sampling a sound file to make a visual effect (such as a graph that moved to the sound). The question was how should the sample from the sound wave be taken. I said average over a time interval (such as 0.1 seconds) and he said that's a bad idea as average can only be used over a normal distribution.
It's been a while since I've studied statistics and would like a simple explination
First: what does normal distribution have to do with anything?
Second: the average can be computed as long as the two numbers can be added and divided by two so I don't know why he used the words "can't use it". What is wrong when using the average when something is not normally distributed?