A specialty coffee roaster claims that their 'Dark Peak' espresso beans contain an average of 14.5 mg of caffeine per gram. A food scientist suspects that recent inconsistencies in roasting temperatures have altered this mean caffeine content. A random sample of 8 grams of beans is analyzed, and the caffeine concentration ccc (in mg/g) for each is recorded below:
14.6,14.9,15.1,14.7,14.5,15.0,14.8,14.8 14.6, \quad 14.9, \quad 15.1, \quad 14.7, \quad 14.5, \quad 15.0, \quad 14.8, \quad 14.8 14.6,14.9,15.1,14.7,14.5,15.0,14.8,14.8Conduct a hypothesis test at the 10% significance level to investigate the scientist's suspicion. You may assume that caffeine concentrations are normally distributed with a standard deviation of 0.4 mg/g.
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.