# Poisson Distribution - on a standard calculator

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• Mar 8th 2011, 10:21 AM
jickjoker
Poisson Distribution - on a standard calculator
hello , can Poisson Distribution problems be worked out on a standard
calculator ?
here is a question ive been trying to solve

If there are 150 typographical errors randomly distributed in a
600-page manuscript, find the probability that any given page has exactly 2 errors.

the solution (2.7183) - 0.25 * (0.25)2 / 2!
the answer given is 0:024

my problem is this part (2.7183) - 0.25
can it be done on a standard calculator ?
if so how?

i apologize for being Old Fashioned
but i like my standard calculator! (Worried)

• Mar 8th 2011, 01:41 PM
mr fantastic
Quote:

Originally Posted by jickjoker
hello , can Poisson Distribution problems be worked out on a standard
calculator ?
here is a question ive been trying to solve

If there are 150 typographical errors randomly distributed in a
600-page manuscript, find the probability that any given page has exactly 2 errors.

the solution (2.7183) - 0.25 * (0.25)2 / 2!
the answer given is 0:024

my problem is this part (2.7183) - 0.25
can it be done on a standard calculator ?
if so how?

i apologize for being Old Fashioned
but i like my standard calculator! (Worried)

Every calculator (including yours) can do the basic opertions of addition, subtraction, multiplication and division. Without wanting to sound facetious, how you do it is that you press the correct buttons in the correct order. It will most likely include using appropriate brackets.

Any problem doing this will be at the user interface, not the calculator. I suggest you ask someone in the flesh to help you if you can't do it.
• Mar 8th 2011, 04:18 PM
awkward
Quote:

Originally Posted by jickjoker
hello , can Poisson Distribution problems be worked out on a standard
calculator ?
here is a question ive been trying to solve

If there are 150 typographical errors randomly distributed in a
600-page manuscript, find the probability that any given page has exactly 2 errors.

the solution (2.7183) - 0.25 * (0.25)2 / 2!
the answer given is 0:024

my problem is this part (2.7183) - 0.25
can it be done on a standard calculator ?
if so how?

i apologize for being Old Fashioned
but i like my standard calculator! (Worried)

The answer should be

$\displaystyle \displaystyle \frac{(0.25)^2}{2!} e^{-0.25}$

It's difficult to compute
$\displaystyle \displaystyle e^{-0.25}$
on a four-function calculator (if that's what you have). So for problems like this you probably want a calculator with an
$\displaystyle \displaystyle e^x$
key, or an
$\displaystyle \displaystyle x^y$
key.