Examples
Examples
Try the starting example
- Mean count
- 2
- Observed count
- 0
- Exact-count probability
- 0.135335
Try another scenario
- Mean count
- 2.2
- Observed count
- 0
- Exact-count probability
- 0.110803
Calculation method
Calculation method
Exact-count probability
exp(-a) × a^b ÷ (factorial(b))
Symbols and units
- a
- Mean count
- b
- Observed count
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Calculation steps and notation
factorial(n) is 1 × 2 × … × n, with factorial(0) = 1. Exact integer arithmetic is used up to n = 500.
exp(x) means e^x, where e is approximately 2.718281828459045.
Assumptions & limits
Assumptions & limits
- Poisson model with a constant mean event rate and independent events.
Are these inputs private?
These calculations run in your browser. A shared link contains the values you choose to share. Only questions submitted to the separate AI finder are sent to OpenAI.
Further reading
Background reading; this does not imply endorsement or independent review of SumFizz.