- #1

- 852

- 50

- Homework Statement
- On average, there are 5 dogs in 100 square miles . What is the probability of 2 dogs in 50 square miles.

- Relevant Equations
- P(X =x) = e^(-lambda) * ( lambda^x/x!) This is the poisson probability eq.

Please excuse me for posting in this group.l There seems to be little activity in the statistics group and i might get no response.

For this example, lambda, is the average of dogs per 100 square miles = 0.05.

if I wanted the probability of 2 dogs in 100 square miles I would calculate..

P(x=2) = e^(-.05) * (0.05^2/2!) = 0.00119

I assume that for the probability of 2 dogs in a 50 square mile area the lambda would be the same, i.e. 5 in 100 square miles would be the same as 2.5 in 50 square miles = 0.05 and the probability would be the same as above.

Where is my thinking wrong?

For this example, lambda, is the average of dogs per 100 square miles = 0.05.

if I wanted the probability of 2 dogs in 100 square miles I would calculate..

P(x=2) = e^(-.05) * (0.05^2/2!) = 0.00119

I assume that for the probability of 2 dogs in a 50 square mile area the lambda would be the same, i.e. 5 in 100 square miles would be the same as 2.5 in 50 square miles = 0.05 and the probability would be the same as above.

Where is my thinking wrong?