The article An Association Between Fine Part ides and Asthma

The article \"An Association Between Fine Part ides and Asthma Emergency Department Visits for Children in Seattle\" [Environmental Health Perspectives June, 1999 107(6)] used Poisson models for the number of asthma emergency department (ED) visits per day. For the zip codes studied, the mean ED visits 1.8 per day What is the probability of more than five visits m a day? 0.010 0.030 0.005 0 050

Solution

Note that P(more than x) = 1 - P(at most x).          
          
Using a cumulative poisson distribution table or technology, matching          
          
u = the mean number of successes =    1.8      
          
x = our critical value of successes =    5      
          
Then the cumulative probability of P(at most x) from a table/technology is          
          
P(at most   5   ) =    0.989621963
          
Thus, the probability of at least   6   successes is  
          
P(more than   5   ) =    0.010378037 = 0.010 [ANSWER, A]