A cashier passes an average of 7 customers an hour. Using Poisson distribution, what is probability that she will pass 2 customers in 2 different 1 hour time frames (i.e between 1:00-2:00 & 3:00-4:00)?

Solution:

since they it's 2 diffent one hour periods, I would think that you would have: , since she can have 0 in the first interval but 2 in the second one, or one in the first and another in the second. Is this correct?