A cosmic ray observatory monitors the frequency of high-energy solar micro-bursts. Records show that the observatory detects an average of 48 micro-bursts per 10-hour cycle. The number of micro-bursts detected per hour is modeled using a Poisson distribution.
Determine the critical region for a two-tailed test of the mean number of detections per hour at a 10% level of significance. The probability of rejection in each tail must be less than 0.05.
Calculate the actual significance level of this test.
A new filtering lens is installed which the lead scientist claims has significantly reduced the sensitivity to these micro-bursts, thereby reducing the mean number of detections.
A random observation period of 50 hours is conducted, and a total of 215 micro-bursts are recorded.
Use a suitable approximation to test the scientist's claim at a 5% level of significance. You should 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.