most important thing is that each cyl is w/in 10 from the others. If you are losing compression it will most likely be in only one, maybe 2 cylinders. Chances of all 4 losing compression and being about the same is not likely.
That being said, those who dont have compression testers, who want a backyard check, do this:
Disable ignition by unplugging coil pack. Crank engine for about 5 seconds straight (car wont start). Listen for what we call, even cranking. There is not points where the engine cranks faster or slower. it should be even.
A trained ear can hear minor compression loss. Major compression loss is obvious.