I'm learning the Poisson distribution and am trying to "backward" calculate lambda if given a random value (k) and cumulative density function value (p). My k value is rather large, over 200, and I'm not even sure if using the poisson is a good idea since it's just looking like a normal distribution at this point. Either way, I'm still interested in trying to figure out if it's possible to calculate lambda given k and p.
I tried to figure it out on my own but I have no clue where to start or how to accomplish this. Ultimately, I'd like to use scipy.stat poisson.
For example, if I have a value of k=400 and p=0.9, I would like to find the value of lambda which would end up being approximately 375.
from scipy.stats import poisson
If anybody knows how to solve this and can help me that would be much appreciated.