Please help, thank you :)

[Kiwigirl]

Can anyone please help me answer this in a simple form so that I can understand it? Thank you.

In a warehouse, accidents have been taking place at the rate of 2 every 3 months.
a) What probability distribution is most likely to model the number of accidents in a 3 month period (This is be selected from either the Binomial, Poisson or normal distribution)? Explain why you have made your choice and give any parameter(s) for the distribution.
b) Find the mean and standard deviation of the number of accidents per year
c) What is the percentage of months with no accidents?
d) If a month is chosen at random, find the probability of at least one accident.

 

[tkhunny]

I guess it didn't stick the first time?

Please go read the definition and a few applications of the Poisson Distribution.

 

[Kiwigirl]

Reply

No sorry I didn't understand it and really do need further help. I have text books at home that I have read over and over to try and understand, that's why I'm here. Probability has never been my specialty and although it's embarressing to have to ask again, I actually want to understand how this question is answered, not just the answers for it.

 

[tkhunny]

Poisson deals nicely with frequency in a given period of time.

You have 2 events in 3 months. This can be modelled as Poisson with \(\displaystyle \lambda\,=\,2\) for periods of 3 months. You can extend or contract this for longer of shorter time periods. For example, for periods of one year, you have four (4) 3-month periods, so a Poisson model with \(\displaystyle \lambda\,=\,2*4\,=\,8\) might be appropriate. After finding \(\displaystyle \lambda\), it is a matter of understanding the properties of the Poisson Distribution. That takes some more reading.