The battery life durations of a specific model of commercial drone are known to follow a normal distribution with a mean of 48.5 minutes48.5\text{ minutes}48.5 minutes and a standard deviation of 3.2 minutes3.2\text{ minutes}3.2 minutes.
A drone of this model is selected at random for testing.
Find the probability that the battery life of this drone is less than 45.0 minutes45.0\text{ minutes}45.0 minutes.
The manufacturer classifies the top 12%12\%12% of these drones, in terms of battery life, as "High-Performance".
Estimate, to 2 decimal places, the minimum battery life a drone must have to be classified as "High-Performance".
390 exam-style questions on OCR (MEI) A Level Maths 2.4 Probability Distributions, covering 2.4.1 Recognise binomial situations, 2.4.2 Probability of success p, 2.4.3 Calculate binomial probabilities, 2.4.4 Mean of the binomial distribution, 2.4.5 Expected frequencies for binomial, 2.4.6 Probability functions and discrete random variables, 2.4.7 Numerical probabilities for a simple distribution, 2.4.8 Normal distribution as a model (A-level only), 2.4.9 Shape of the Normal curve (A-level only), 2.4.10 Linear transformation and standardising (A-level only), 2.4.11 Symmetry and inflection of Normal curve (A-level only), 2.4.12 Calculate probabilities from a Normal distribution (A-level only), 2.4.13 Model with probability distributions, and 2.4 Probability Distributions. Each one has a worked solution and a mark scheme showing where the marks go.