Two satellite communication systems, Alpha and Beta, are being tested for signal latency. The latency of system Alpha, measured in milliseconds, is normally distributed with mean 85 and variance 12. The latency of system Beta, measured in milliseconds, is normally distributed with mean 81.5 and variance 18. The latencies for Alpha and Beta are independent. A single test packet is sent through each system.
Find the probability that the latency for the test packet on system Alpha is less than the latency on system Beta.
A transmission sequence consists of 60 packets. Assuming that the packets are sent simultaneously and all latencies are independent, find the probability that the total latency of system Alpha exceeds the total latency of system Beta by more than 250 milliseconds.
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.