A laboratory centrifuge operates at discrete vibration stages V V\,V where V∈{1,2,3,4,5,6,7,8}V \in \{1, 2, 3, 4, 5, 6, 7, 8\}V∈{1,2,3,4,5,6,7,8}, and each stage is equally likely to occur during a test cycle.
Determine the mean and the variance of VVV.
The centrifuge is monitored over 60 independent test cycles. By applying the Central Limit Theorem, calculate an estimate for the probability that the average vibration stage Vˉ\bar{V}Vˉ of these 60 cycles is less than 4.1.
390 exam-style questions on OCR A Level Maths 2.4 Statistical Distributions, covering 2.4.1 Discrete probability distributions, 2.4.2 Binomial distribution as a model, 2.4.3 Calculating binomial probabilities, 2.4.4 Mean and variance of the binomial (A-level only), 2.4.5 Normal distribution as a model (A-level only), 2.4.6 Probabilities using the normal distribution (A-level only), 2.4.7 Links to histograms, mean and standard deviation (A-level only), and 2.4.8 Selecting an appropriate distribution (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.