Homework problem: toss a fair coin 400 times. use the central limit theorem to find an approximation for the probability of at most 190 heads.

This seems like it should be simple (it probably is, sorry!) but I have tried to tackle it with both histogram correction and without and neither have turned up the correct answer.

With histogram correction I wind up with .8289, while the answer is .1711.

Without correction I can't get any answer. The answer manual lists .1587 as the answer without histogram correction.

Any help would be fantastic! Thank you!