The mass of sugar in a standard packet is modelled by a normal distribution with a mean of 1000 g and a standard deviation of 20 g.
Using this model, find the probability that a randomly selected packet contains more than 1035 g of sugar.
A quality control inspector suspects that the filling machine is overfilling and the mean mass is greater than 1000 g. A random sample of 25 packets is taken and the mean mass is found to be 1010 g. Test the inspector's suspicion at the 5% level of significance. State your hypotheses clearly.
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.