The mass of flour in bags packed by a factory is normally distributed with a mean of 1500 g and a standard deviation of 25 g.
Find the probability that a randomly selected bag of flour has a mass of less than 1450 g.
A quality inspector believes the bagging machine is under-filling and the mean mass is less than 1500 g.
State the null and alternative hypotheses for this test.
A random sample of 16 bags is weighed and the mean mass is found to be 1485 g.
Test the inspector's belief at the 1% significance level.
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.