A machine is designed to fill bags of sugar with a target mean weight of 500 g. The weight of sugar in a bag is normally distributed. A quality control manager suspects the machine is underfilling the bags. The weights, xxx g, of 10 randomly selected bags are recorded, and the following statistics are calculated:
xˉ=492.5s=9.24 \bar{x} = 492.5 \quad s = 9.24 xˉ=492.5s=9.24Stating your hypotheses clearly, test at the 5% significance level whether or not the manager's suspicion is supported.
316 exam-style questions on OCR A Level Maths 2.5 Statistical Hypothesis Testing, covering 2.5.1 The language of hypothesis testing, 2.5.2 Hypothesis test for a binomial proportion, 2.5.3 Inference and significance level, 2.5.4 Sample mean as a random variable (A-level only), 2.5.5 Hypothesis test for the mean of a normal distribution (A-level only), 2.5.6 Pearson's product-moment correlation coefficient, and 2.5.7 Hypothesis test using Pearson's coefficient (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.