The lifetime of a certain type of battery is normally distributed with a mean of 60 hours. Given that 8% of the batteries last less than 48 hours, find the standard deviation of the lifetimes.
284 exam-style questions on CCEA A Level Maths 4.5 Statistical distributions (A-level only), covering 4.5.1 Statistical distributions (A-level only) and 4.5.2 Statistical distributions (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.