Randbin

Date: 03/14/99 at 17:38:36
From: Robert Nadler
Subject: Randbin

Consider an airplane that has 113 seats. Based upon past experience
we know that 90% of the customers who have purchased tickets for this 
flight actually check in. If 120 tickets are sold for the flight, what 
is the probability that at most 113 will check in?

Using my calculator to simulate one flight, what does Randbin(120, 0.9) 
mean? What does each number in the randbin mean in terms of the 
problem?

From: Dr. Pat
Date: Sunday, March 14, 1999 4:10 PM
Subject: Randbin

The computation randbin(120, 0.9) simulates a single binomial trial of 
the event that (in your problem) 120 people bought tickets and each has 
an independent probability of 0.9 of showing up for the trip. The 
number you get should be an integer representing the number of people 
who show up on that trip. Press enter again and you get another 
simulated trip. Do it 100 times and then count how many are less than 
or equal to 113 and you get an estimate of the true proportion of the 
time it might happen in real life (if your assumptions are valid).

Numbers near 90% of 120 should show up the most, and numbers near zero 
or 120 should show up less frequently.

- Doctor Pat, The Math Forum
  http://mathforum.org/dr.math/