Poisson Probability Function :- P(x)
P(x) = e- mmx / x !
m = n * p (value between 0 to 10 )
  Enter the x value
  Enter the probability value(p)
  Enter no. of trials(n)
  Find the m value(mean=variance=m)
  Find x !
Value of P(x)
Standard Devin.(sd)
Poisson Distribution Characterstics

1. Discrete Probability Distribution.
2. Main parameter is mean which is equal to np where n is no. of trials , p is probability.
3.It is positively skewed distribution.
4.Mean = variance = m = np
5. Standard Deviation = m^ 1/2
6. skewness = 1/m^1/2
7. kurtosis = 1/ m
8. m normally lies between 0 , 1 and 10.
9. p is small and n is quite large .


1. Events are independent .
2. Probability of a single occurence of the event in a given interval is proportional to the length of the interval.
3.Probability of occurance of more than one event in a very small interval is negligible .


1. no. of defective blades in a pack of 100 .
2. no. of cars passing a certain point in a minute .
3. no. of persons born deaf and dumb per year in a city .
4. no. of typographical errors per page .
5. no. of deaths per day in a district or town in one year by a disease but not epidemic.
6. no. of telephone calls received at a particular switch board per minute during a certain hour of the day .