Class notes (originally in Catalan). Published section by section as the unit unfolds.
Discrete random variable and probability mass function, Bernoulli trial, binomial distribution $X\sim B(n,p)$ with the formula $P(X{=}k)=\binom{n}{k}p^k q^{n-k}$, binomial coefficients, expectation $E(X)=np$ and standard deviation $\sigma=\sqrt{npq}$. Includes a worked penalty-kick example and 6 exercises with hidden solutions.