Moderate -0.8 This is a straightforward application of the Poisson approximation to the binomial distribution with clear parameters (n=800, p=0.005, np=4). The question requires only recognizing the standard conditions (large n, small p), calculating λ=np, and finding P(X≤6) from tables—all routine S2 techniques with no problem-solving insight needed.
1 A newspaper article consists of 800 words. For each word, the probability that it is misprinted is 0.005 , independently of all other words. Use a suitable approximation to find the probability that the total number of misprinted words in the article is no more than 6 . Give a reason to justify your approximation.
1 A newspaper article consists of 800 words. For each word, the probability that it is misprinted is 0.005 , independently of all other words. Use a suitable approximation to find the probability that the total number of misprinted words in the article is no more than 6 . Give a reason to justify your approximation.
\hfill \mbox{\textit{OCR S2 2009 Q1 [4]}}