Sound Testing Frequencies

I've been having a hard time with one of our assignments in the 9th week of our course in Digital Media Skills. Frankly, I have absolutely failed at being able to guesstimate the range of frequencies among certain sounds in our homes. I've read what others estimated, but still, none of it made sense. Finally I created a pictorial graph of how each sound compared to the other sounds. I can see many things from this graph, but still I'm no closer to guessing what the sound frequencies are of my old desktop computer or my new air cleaner. I've continued to explore the excellent Australian site Physclips. But still I wavered. Finally I found a better demonstration of frequency ranges, using this video on YouTube, by Beeps, Chirps, and Noise. Let's hope I can come up with 5 guesses by 11:55pm tonight!