Suppose that the number of claims tht may arise for a 'portfolio' of 300 insurance policies in a year is modeled as a poisson random variable, with mean m. Suppose that 30 claims occured from this portfolio in year 2005. Find the p-value of this result in a test of
H0:m=36 verses H1:m<36

I dont think what im doing is right...

P[X ≥ 30|µ=36]

P[(X-36)/(σ/√36) ≥ (30-36)/(σ/√36)]

P[Z ≥ -6/(σ/6)]

How do you find σ?