Whooping cough (pertussis) is a highly contagious bacterial infection that was a major cause of childhood deaths before the development of vaccines. About 80% of unvaccinated children who are exposed to whooping cough will develop the infection, as opposed to only about 5% of vaccinated children.

A group of 20 children at a nursery school are exposed to whooping cough by playing with an infected childIf all 20 have been vaccinated, what is the mean number of new infections?

Question

Ansley Howell

30 July, 07:54

+1

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Alina Hodge · Answer 1

A, since n=20 and p=5% if children are vaccinated mean number of new infections = np = 20*0.05=1 p (x<=2) = P (x=0) + P (x=1)