The flight times of a particular model of reconnaissance drone, T T\,T minutes, are normally distributed with an unknown mean μ \mu\,μ and a known standard deviation σ\sigmaσ. A random sample of 144 flights provided a 98% confidence interval for μ \mu\,μ of (45.837,48.163)(45.837, 48.163)(45.837,48.163).
Without carrying out any further calculations, use this confidence interval to test whether or not μ=48.5\mu = 48.5μ=48.5. State your hypotheses clearly and write down the significance level you have used.
A second study of 200 flights recorded a mean flight time of 46.2 minutes.
Determine a 90% confidence interval for μ \mu\,μ based on this second study.
355 exam-style questions on OCR (MEI) A Level Maths 2.5 Statistical Hypothesis Testing, covering 2.5.1 Process and language of hypothesis testing, 2.5.2 When to apply 1-tail and 2-tail tests, 2.5.3 Significance level and incorrect rejection, 2.5.4 Null and alternative hypotheses (binomial), 2.5.5 Conduct a binomial hypothesis test, 2.5.6 Critical and acceptance regions (binomial), 2.5.7 Distribution of the sample mean (A-level only), 2.5.8 Hypothesis test for a single mean (A-level only), 2.5.9 Critical and acceptance regions (mean) (A-level only), 2.5.10 Correlation as closeness to a straight line (A-level only), 2.5.11 Inference using a correlation coefficient (A-level only), and 2.5 Statistical Hypothesis Testing. Each one has a worked solution and a mark scheme showing where the marks go.