Edexcel S3 2013 June — Question 8

Exam BoardEdexcel
ModuleS3 (Statistics 3)
Year2013
SessionJune
TopicLinear combinations of normal random variables
TypeSame variable, two observations

8. A farmer supplies both duck eggs and chicken eggs. The weights of duck eggs, \(D\) grams, and chicken eggs, \(C\) grams, are such that $$D \sim \mathrm {~N} \left( 54,1.2 ^ { 2 } \right) \text { and } C \sim \mathrm {~N} \left( 44,0.8 ^ { 2 } \right)$$
  1. Find the probability that the weights of 2 randomly selected duck eggs will differ by more than 3 g .
  2. Find the probability that the weight of a randomly selected chicken egg is less than \(\frac { 4 } { 5 }\) of the weight of a randomly selected duck egg. Eggs are packed in boxes which contain either 6 randomly selected duck eggs or 6 randomly selected chicken eggs. The weight of an empty box has distribution \(\mathrm { N } \left( 28 , \sqrt { 5 } ^ { 2 } \right)\).
  3. Find the probability that a full box of duck eggs weighs at least 50 g more than a full box of chicken eggs.