***** Distributions 82 (freeware)
***** by Daniel J. Bishop
***** danb2k@hotmail.com

Notepad users: Turn on word wrap.

This program is part of the StatKit 82 project, which will make most of the TI-83's statistics functions available to TI-82 users.

To use this program, copy DISTR.82P to your calculator using TI-Graph Link.  After you've done this:

1.  Run DISTR from the PRGM menu.
2.  Enter the parameters for the function (see below)
3.  The number displayed on the last line is the desired probability.

StatKit 82 will be released this June.  For more information, please e-mail me at danb2k@hotmail.com

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Binomial Distribution

N=number of trials
P=probability of success

1:BINOMPDF
TI-83 syntax: binompdf(N,P,X)
returns: probability of exactly X successful trials

2:BINOMCDF
TI-83 syntax: binomcdf(N,P,X)
returns: probability of at most X successful trials

Example:
The U.S. unemployment rate is 4 percent.  If 100 Americans who are in the labor force are selected at random, what is the probability that
a) four are unemployed?
b) less than four are unemployed?

Solutions:
a) P(X=4)=binompdf(100,.04,4)=.1994
b) P(X<4)=P(X<=3)=binomcdf(100,.04,3)=.4295

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Geometric Distribution

P=probability of success

3:GEOMETPDF
TI-83 syntax: geometpdf(P,X)
returns: probability that the first success is on the Xth trial

4:GEOMETCDF
TI-83 syntax: geometcdf(P,X)
returns: probability that the first success is on or before the Xth trial

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Poisson Distribution

lambda (L)=mean number of times an event occurs within a given time period

5:POISSONPDF
TI-83 syntax: poissonpdf(lambda,X)
returns: probability that the event will occur exactly X times

6:POISSONCDF
TI-83 syntax: poissoncdf(lambda,X)
returns: probability that the event will occur at most X times

Example: On average, I receive 10 e-mails per day.  What is the probability that
a) I will get exactly twelve e-mails tomorrow?
b) I will get no more than 50 e-mails next week?
Assume a poisson distribution.

Solutions:
a) P(X=12|lambda=10)=poissonpdf(10,12)=.0948
b) P(X<=50|lambda=70)=poissoncdf(70,50)=.0075
   lambda is multiplied by 7 because there are 7 days in a week.

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7:EXIT

self-explanatory.  Use this option if you realize you're running the wrong program.