The resistance of a specific type of resistor is normally distributed with a mean of 10.2 ohms and a standard deviation of 0.15 ohms.
Find the probability that a randomly selected resistor has a resistance of less than 10.0 ohms.
Write down the null and alternative hypotheses to test if the mean resistance is less than 10.2 ohms.
A sample of 10 resistors is measured and the mean resistance is found to be 10.1 ohms. Carry out a test at the 1% significance level to see if there is evidence that the mean resistance is less than 10.2 ohms.
390 exam-style questions on OCR A Level Maths 2.4 Statistical Distributions, covering 2.4.1 Discrete probability distributions, 2.4.2 Binomial distribution as a model, 2.4.3 Calculating binomial probabilities, 2.4.4 Mean and variance of the binomial (A-level only), 2.4.5 Normal distribution as a model (A-level only), 2.4.6 Probabilities using the normal distribution (A-level only), 2.4.7 Links to histograms, mean and standard deviation (A-level only), and 2.4.8 Selecting an appropriate distribution (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.