Rookie needs guidance for compression test

We are assuming you have a screw-in compression gage. The rubber tipped "hold it tight" ones can give erratic results. I would remove all spark plug tubes and try again, in case it is leaking past that gap. Also, replace all the rubber tube seals since cheap and you don't want a "drool tube". If your measurements above are valid, #5 is a bit weak, probably leaking past the rings. You would likely find the cylinder walls scored a bit if you pulled the head, but no need for that yet.

Once it gets below ~70 psig, you might start finding the spark plug totally clean (washed w/ unburned gas). If a cheap bastard like me, you could then improve mpg by removing the lifters and push-rods on that cylinder (not possible for later "peanut" heads) so it doesn't flow fuel uselessly. After bragging about my "5 cyl slant" 1969 Dart to a co-worker he said that without the lifters it would lose oil pressure (he was a Chevy/Ford rodder), so I re-installed, adjusted the push-rods to not open and added weak springs to keep from rattling. I now know that is not needed for a slant since the lifter bores have no oil feed. I drove that way fine for a year then installed a rebuilt long block and rebuilt tranny. 4 months later the car was stolen and never recovered (license plate found on a stolen Jetta 7 yrs later). I hope your best efforts aren't similarly rewarded.