This

**preview**shows half of the first page. to view the full**2 pages of the document.**Poisson probability

1) Large # of trials; n>100

Small probability of success; np<10

2) An observed probability of success over a given time period; Num of fish/hour

λ = Mean number of success over a given time period

r = # of successes over same time period

NOTE: λ and r have same time period

Ex: Police officer observed that on average, he stops 0.7 people per hour.

λ = 0.7ppl/1hr

What are the probability in a 8hr shift?

λ = (0.7ppl/1hr)(8hrs/8hrs)

= 5.6ppl/8hr

P(r) = (e- 5.6* 5.6r)/r! probability of pulling over r people in an 8hr shift

= (e- 5.6* 5.65)/5!

= 0.169711

**HOW TO DO THIS ON CALCULATOR: shift button, dot button, (negative button), 5.6 times 5.6, yx, 1

divide 1, shift button, 4

λ = (given probability/1 hr) * new time fram

Chap 6: Normal Distribution

1) Bell shaped

P(r) =

(e−λ)∗(λ)r

r !

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