Whooping cough (pertussis) is a highly contagious bacterial infection that was a major cause of childhood deaths before the development of vaccines. About 80%80% of unvaccinated children who are exposed to whooping cough will develop the infection, as opposed to only about 5%5% of vaccinated children. A group of 2020 children at a nursery school is exposed to whooping cough by playing with an infected child.
(a) If all 2020 have been vaccinated, what is the mean number of new infections? (Enter your answer as a whole number.)
mean number of new infections =
(b) If none of the 2020 have been vaccinated, what is the mean number of new infections? (Enter your answer as a whole number.)
mean number of new infections =
(c) What is the probability that 1818 or more of the 2020 children develop infections? (Enter your answer rounded to four decimal places.)

the answer   is 200

step-by-step explanation:

this is a problem about poisson probabilities.   i don't know if you've

already studied poisson distributions, or if you have a place to look

to read more about the subject.  

here's how you can see a poisson distribution coming.   when there are

a lot of events that may happen at any time (or any place), and when

you're counting how many of them happen at a particular time (or a

particular place), and each event is independent of the others, then

the result is a poisson distribution.   this is roughly true for the

chocolate chips; one chip being in a cookie has only a small effect on

the probability that another chip will be in the cookie.

once you know you have a poisson distribution, you know a lot.   there

is only one parameter to a poisson distribution, so if you know the

mean, you know everything.   the form of the distribution is

  probability of n chips = {[e^(-x)]*(x^n)} / (n! )

he kicked it up? is this the answer ?

step-by-step explanation:

i need a diagram

step-by-step explanation:

no

i'm a sophomore in connections, i'd recommend checking on jishka.com they have a large range of questions and answers from our school.