Standard +0.3 This requires knowing that independent Poisson distributions sum to another Poisson (mean 6+8=14), then calculating P(X≥16) using tables or complement. It's a straightforward application of standard Poisson properties with minimal problem-solving beyond recognizing the sum property.
1 On a motorway, lorries pass an observation point independently and at random times. The mean number of lorries travelling north is 6 per minute and the mean number travelling south is 8 per minute. Find the probability that at least 16 lorries pass the observation point in a given 1 -minute period.
1 On a motorway, lorries pass an observation point independently and at random times. The mean number of lorries travelling north is 6 per minute and the mean number travelling south is 8 per minute. Find the probability that at least 16 lorries pass the observation point in a given 1 -minute period.
\hfill \mbox{\textit{OCR S3 2016 Q1 [4]}}