A high-precision voltage regulator is tested for drift during calibration. In each micro-adjustment step, the voltage deviation VVV is an integer millivolt value where V∈{−3,−1,1,3}V \in \{-3, -1, 1, 3\}V∈{−3,−1,1,3}, with each value being equally likely.
Determine the mean and the variance of VVV.
A sequence of 150 independent micro-adjustments is performed. Using the Central Limit Theorem, calculate an approximation for the probability that the average voltage deviation of these 150 adjustments is less than -0.25.
616 exam-style questions on Edexcel A Level Maths The Normal Distribution, covering 3.1 The Normal Distribution, 3.2 Finding Probabilities for Normal Distributions, 3.3 The Inverse Normal Distribution Function, 3.4 The Standard Normal Distribution, 3.5 Finding the mean and standard deviation, 3.6 Approximating a Binomial Distribution, and 3.7 Hypothesis Testing with the Normal Distribution. Each one has a worked solution and a mark scheme showing where the marks go.