How to calculate normal takeoff ground roll when the POH only has Short Field Takeoff tables?
In the C172S POH I have, it's on p. ii (Performance - Specifications): 960ft ground roll and 1630ft total over a 50ft obstacle. The note on p. iii says:


  The above performance figures are based on airplane weights at 2550
  pounds, standard atmospheric conditions, level, hard-surfaced dry
  runways and no wind. They are calculated values derived from flight
  tests conducted by Cessna Aircraft Company under carefully documented
  conditions and will vary with individual airplanes and numerous
  factors affecting flight performance.


In other words, it's a useful number to know but you're unlikely to get exactly that performance unless you're a Cessna test pilot in a brand new aircraft. If you own the aircraft (or rent it often) you might want to spend some time actually measuring takeoff distances yourself, to see what performance you're really getting.