The discharge duration, D D\,D minutes, of a specialized drone battery is modeled by a normal distribution with a mean of 122.5 minutes and a standard deviation of 3.2 minutes.
Find the probability that a randomly selected battery has a discharge duration exceeding 128 minutes.
Determine the value of d d\,d such that P(122.5<D<d)=0.38P(122.5 < D < d) = 0.38P(122.5<D<d)=0.38.
Two batteries are selected at random from the production line.
Calculate the probability that exactly one of these batteries has a discharge duration between 122.5 minutes and d d\,d minutes.
328 exam-style questions on WJEC A Level Maths 4.2 Statistical distributions (A-level only), covering 4.2.1 Statistical distributions (A-level only), 4.2.2 Statistical distributions (A-level only), and 4.2.3 Statistical distributions (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.