Cumulative Probability
The probability that a random variable takes a value less than or equal to a specified number. It's the area under the distribution curve up to that point.
Like asking "what percentage of students scored below 80?" rather than "what percentage scored exactly 80?"
Why it matters
P(over) is literally 1 minus the cumulative probability at the prop line — understanding this concept is understanding how prop probabilities are calculated.
How DMP uses this
DMP computes cumulative probabilities using the normal CDF (or Poisson CDF for discrete stats) to determine the exact probability of a player going over or under a given line.
Common mistake
Confusing the probability of exactly hitting a number with the probability of being at or below it — cumulative probability includes all values up to the threshold.