OCR MEI Further Statistics A AS 2019 June — Question 2

Exam BoardOCR MEI
ModuleFurther Statistics A AS (Further Statistics A AS)
Year2019
SessionJune
TopicPoisson Distribution
TypePoisson approximation justification or comparison

2 Almost all plants of a particular species have red flowers. However on average 1 in every 1500 plants of this species have white flowers. A random sample of 2000 plants of this species is selected. The random variable \(X\) represents the number of plants in the sample that have white flowers.
  1. Name two distributions which could be used to model the distribution of \(X\), stating the parameters of each of these distributions. You may use either of the distributions you have named in the rest of this question.
  2. Calculate each of the following.
    • \(\mathrm { P } ( X = 2 )\)
    • \(\mathrm { P } ( X > 2 )\)
    • A random sample of 20000 plants of this species is selected.
    Calculate the probability that there are at least 10 plants in the sample that have white flowers.