A botanical research study finds that 45% of seeds from a specific hybrid perennial germinate within the first 10 days of being sown. The seeds are packaged in sachets of 20 for commercial sale. A sachet is selected at random.
Determine the probability that the sachet contains exactly 9 seeds that germinate within 10 days.
Determine the probability that there are at least 13 seeds in the sachet that germinate within 10 days.
Using a suitable approximation, find the probability that in a bulk tray of 200 seeds, between 80 and 105 seeds (inclusive) germinate within 10 days.
390 exam-style questions on OCR (MEI) A Level Maths 2.4 Probability Distributions, covering 2.4.1 Recognise binomial situations, 2.4.2 Probability of success p, 2.4.3 Calculate binomial probabilities, 2.4.4 Mean of the binomial distribution, 2.4.5 Expected frequencies for binomial, 2.4.6 Probability functions and discrete random variables, 2.4.7 Numerical probabilities for a simple distribution, 2.4.8 Normal distribution as a model (A-level only), 2.4.9 Shape of the Normal curve (A-level only), 2.4.10 Linear transformation and standardising (A-level only), 2.4.11 Symmetry and inflection of Normal curve (A-level only), 2.4.12 Calculate probabilities from a Normal distribution (A-level only), 2.4.13 Model with probability distributions, and 2.4 Probability Distributions. Each one has a worked solution and a mark scheme showing where the marks go.