Can anyone explain this concept in a really low level way without usinging any notations (just words)?
I just can’t seem to get it despite it seeminly incredibly straight forward. I tried google and other sources but it is explained with notations which I don’t quite get either…
The cumulative distribution is just the sum of all probabilities up to a given number; it gives the probability that a random variable is less than or equal to a given number. At theleft end it’s zero (the probability that you’re less than the smallest possible number is zero), and at the right end it’s one (the probability that you’re less than or equal to the largest number is one).
For example, if there are four possible outcomes – 1, 2, 3, and 4 – and the probabilities are: P(X = 1) = 0.1, P(X = 2) = 0.2, P(X = 3) = 0.3, and P(X = 4) = 0.4, then the cumulative density function F(x) is:
F(0) = 0 (you can’t get zero)
F(1) = 0.1
F(2) = 0.3 (if it’s less than or equal to 2, then it’s either 1 (P = 0.1) or it’s 2 (P = 0.2))
F(3) = 0.6 (= 0.1 + 0.2 + 0.3)
F(4) = 1.0
F(5) = 1.0)
and so on.
For continuous probability functions, you need calculus to get the cumulative distribution function. Yuck.
Perfect.
Thanks to both of you.
You’re welcome.