The problem i have seems very easy but i am just not sure. There is a number of calls per hour ( from 8-12) received by customer service. Mon 1,3,0,5 Wed 2,0,0,1 Fr 4,2,1,0 So now what is the relative frequncy for n calls per hour? Total number of calls is 19. So for n=5 it is 1/19 =5.2%. For n=2 it is 2/19= 10.5%. And for n=0 it is 4/19 = 21%?? Is it right with the zero? Is the mean value of calls 19/12=1.5 per hour? To calculate the probability of having 2 calls is it enough to stick the mean value and the 2 into the poissons formula? Would appreciate the help.