(a)[4]
Calculate the value of $\mathrm{Var}(X)$.
(b)[3]
Kai spins his spinner 10 times. Calculate the probability that a score of 2 is obtained fewer than 8 times.
Mathematics 9709 · AS & A Level · Discrete random variables
Discrete random variables — practice question
Kai owns a spinner with four sides, marked 1, 2, 3, 4. Each time it is spun, the score equals the number on the face where it stops. The random variable $X$ represents this score. The probability distribution table for $X$ appears below.