the only real way to measure is by high speed camera and professional tests. sometimes you can find these done or sometimes the manufacturer provides them however they can vary greatly depending on what tests are ran and how they are ran. you cant treat it as an exact number in any case as its variable.
from a quick search i was unable to easily find a response time listed for that model. the manufacturer also doesnt report it.
you can try to find some reviews and perhaps one does a high speed test for response time measurement but you may have to spend hours to look for it (if one even exists). or you could ask samsung directly (though i doubt you will get a solid answer)