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Cumulative distribution function¶

It is a function \(F_X: R \rightarrow [0,1]\) which sprecifies a probability measure:

\[ F_X(x) = P(X \le x) \]

This is the probability that a random variable will be less then \(x\). We can use it to calculate the probability that a random variable will be within some bounds \(a,b\) where \(a < b\).

Properties¶

  • \(0 \le F_X(x) \le 1\)

  • \(\lim_{x \rightarrow - \infty} F_X(x) = 0\)

  • \(\lim_{x \rightarrow \infty} F_X(x) = 1\)

  • \(x \le y \Leftrightarrow F_X(x) \le F_X(y)\)