Tag Archives: MDR_math230_HW4_F14

Boxes without toys

A cereal company advertises a prize in every box of its cereal. In fact, only about 95% of the boxes have a prize in them. If a family buys one box of this cereal every week for a year, estimate the chance that they will collect more than 45 prizes. What assumptions are you making ?


[Pitman p122, # 9]

Random Errors in a Book

A book has 200 pages. The number of mistakes on each page is a Poisson random variable with mean 0.01, and is independent of the number of mistakes on all other pages.

  1. What is the expected number of pages with no mistakes ? What is the variance of the number of pages with no mistakes ?
  2. A person proofreading the book finds a given mistake with probability 0.9 . What is the expected number of pages where this person will find a mistake ?
  3. What, approximately, is the probability that the book has two or more pages with mistakes ?


[Pitman p235, #15]