alleryStart learning →The **cumulative distribution function (c.d.f.)** $F(x)$ of a discrete random variable is:
- $F(x) = P[X = x]$
- $F(x) = 1 - p$
- $F(x) = P[X \leq x] = \sum_{x_i \leq x} p_i$
- $F(x) = P[X > x]$
Show answer and solution
Correct answer: C. $F(x) = P[X \leq x] = \sum_{x_i \leq x} p_i$
c.d.f.
accumulates: $F(x) = P[X \leq x] = \sum_{x_i \leq x} p_i$.
It is non-decreasing, starts at 0 (for $x < \min$), reaches 1 (at $x \geq \max$).
For discrete RV it's a step function.