CumulativeDensityFunction.md (774B)
1 # Cumulative Density Function (CDF) 2 3 Prob L8 4 5 **Definition:** A cumulative density function is a function of a random variable where any given value is the probability of getting an output less than or equal to the current value. 6 7 This is defined mathmatically as F(x) = P(X \leq x). 8 9 The value of a CDF is it combines discrete probability functions (PMFs) and continuous probability functions (PDFs) into one function definition resolving the need to do multiple computations for both. 10 11 Note: CDFs sum up to an arbitrary value, but the value at F(inf) should always be 1. 12 13 ## Values 14 15 With a CDF we find the probability of a value or less than it being selected as the value F(x). 16 17 When finding the probability of a range we subtract the end from the start of the range.