(i)[4]
Find the values of $\mu$ and $\sigma$.
(ii)[2]
Find the probability that, among 6 random values of $X$, exactly 4 are greater than $25$.
Mathematics 9709 · AS & A Level · Continuous random variables
Continuous random variables — practice question
Suppose the random variable $X$ has a normal distribution, with mean $\mu$ equal to three times the standard deviation $\sigma$. It is also given that $\mathrm{P}(X < 25) = 0.648$.