A food processing plant packs cereal into boxes with a targeted mean mass of 500 g.
A consumer protection agency claims that the boxes are being underfilled on average.
To investigate, they weigh a sample of boxes and find the following:
n=250∑x=124625∑x2=62145000 n = 250 \quad \sum x = 124625 \quad \sum x^2 = 62145000 n=250∑x=124625∑x2=62145000Find the mean and standard deviation of the sample.
Carry out a hypothesis test to test the agency's claim at the 1% significance level. State your assumptions clearly.
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.