4.7 Discrete random variables and expected valueIB Maths: Applications and Interpretation HL: Mind map

Exam questions on 4.7 Discrete random variables and expected value

1. The discrete random variable $X$ has the probability distribution $P(X=1)=0.1$, $P(X=2)=0.3$, $P(X=3)=0.4$ and $P(X=4)=k$.
   Find $P(X\geq3)$.2 marks
2. The discrete random variable $X$ has probability distribution $P(X=x)=\frac{x+4}{18}$ for $x\in\{1,2,3\}$.
   Find $P(X\geq2)$.2 marks
3. At a fairground, a player pays 4 AED to spin a wheel. The prize is 0 AED with probability 0.5, 6 AED with probability 0.3 and 10 AED with probability 0.2. Let $X$ be the prize in AED.
   Find $\mathrm{E}(X)$.3 marks