Statistics, Poisson Probability Distribution: *I'm using a TI Nspire CX - If you can help with the right Poisson command that would be great!

A person with a cough is apersona non grataon airplanes, elevators, or at the theater. In theaters especially, the irritation level rises with each muffled explosion. According to Dr. Brian Carlin, a Pittsburgh pulmonologist, in any large audience you'll hear about13coughs per minute.

(c) Find the probability of at leastninecoughs (in a large auditorium) in a30-second period. (Use 4 decimal places.)

*******I understand how to use the poissCdf, though the (30-second period) is throwing me off! Thx!