Consider a random variable $X$ that takes values $+1$ and $−1$ with probability $0.5$ each. The values of the cumulative distribution function $F(x)$ at $x = −1$ and $+1$ are
This might help ...
All good links I find are updated in respective subject pages in gatecse under weblinks- you can see here:
http://gatecse.in/probability/
probability distribution
http://web.archive.org/web/20151010091326/http://web.stanford.edu:80/~iwright/PP%20Materials/Lesson%206%20Probability%20Distributions%20Notes.pdf
Gatecse