The weights of bags of sugar, WWW grams, are normally distributed such that W∼N(μ,1.22)W \sim \text{N}(\mu, 1.2^2)W∼N(μ,1.22).
Given that 25%25\%25% of the bags weigh more than 502502502 grams, find the value of μ\muμ to the nearest 0.10.10.1 g.
An employee selects 151515 bags at random.
Find the probability that fewer than 222 of these bags weigh more than 502502502 grams.
A wholesaler selects 200200200 bags at random.
Using a suitable approximation, find the probability that more than 555555 of these bags weigh more than 502502502 grams.
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.