Assuming the number of visits made by employee has a poisson distribution ,test the hypothesis that the annual mean per employee is greater than 3.

I am using the graphical method and I am not sure of which p[X=x] should i consider.

X: no.of visits by each employee to the doctor.

H0:lambda=3

H1:lambda>3

X follows a Poisson(3)

Then what is the probability that I should check?

What I did was as the average of sample data is 4,calculated

**p[X=4]**and checked if it was in the critical region. Is this the correct probability to calculate?