mste.illinois.edu Open in urlscan Pro
128.174.67.206  Public Scan

Form analysis
0 forms found in the DOM

Text Content

Skip To Content (Alt+0)SkipToSkip To Content
Landmark Regions

Headings


College of Education


OFFICE FOR MATHEMATICS, SCIENCE, AND TECHNOLOGY EDUCATION

Home About
 * About MSTE
 * MSTE Personnel
   

Resources Projects
 * Featured Projects
 * Past Projects

Contact
 * Contact MSTE
 * Directions to MSTE
 * Contact Form

Home Activity Birthday


THE BIRTHDAY PROBLEM

 * Introduction
 * Simulation
 * Questions
 * An Explanation
 * A Note to the Teacher
 * Contact us with comments


INTRODUCTION

Happy Birthday! There's a birthday in your class today! Or will there be two?
How likely is it that two people in your class have the same birthday? Say your
class has 28 students.

There are a number of ways to approach this problem. The most common is to take
a survey and see if it happens that two birthdays fall on the same day. But if
it happens in the surveyed class, will it occur in another class with different
students? The question of how likely it is for any given class is still
unanswered.

Another way is to survey more and more classes to get an idea of how often the
match would occur. This can be time consuming and may require a lot of work. But
a computer can help out. Below is a simulation of the birthday problem. It will
generate a random list of birthdays time after time.


SIMULATION

Choose a number for your class size and run several trials with that size. The
simulation will graph the average calculated probability of each class size. The
list on the right will display the last set of birthdays generated.

The results table at the bottom of the simulation will display trial statistics
for the current class size.

The class size can be changed by clicking on the graph, entering a new number in
the text box, or using the arrow keys while the graph is selected.

Class Size (1-60):
Run 1 trial Run 100 trials Reset



GRAPH:


BIRTHDAYS:


Click in the grid or type a number between 1 and 60 to select the size of the
group to simulate. Then click Calculate a few times to see the likelihood that 2
people in a group of that size have the same birthday.
Note: Duplicate birthdays will be highlighted and in bold
Contains trial statistics such as experimental probability or average number of
duplicate dates

Results Number of dates duplicated 0 Average # of dates duplicated 0 Trial
effect on average 0 Experimental probability 0 Number of trials 0

Class size is 15. Experimental probability is not yet calculated.

Now what do you think the probability of a match is? It may surprise you that
there were so many matches. Let's look at an explanation for this problem.


CREDITS

Applet Source, Written by Nicholas Exner, modified by Michael McKelvey,
converted to javascript and HTML5 by Daniel Hefner.

Office for Mathematics, Science, and Technology Education

College of Education

 * Facebook
 * Twitter
 * YouTube


EXPLORE:

 * Resources
 * Projects


CONNECT:

 * About Us
 * Contact Us

 * Log In
 * Privacy Policy
   
 * Accessibility
 * Copyright © 1994-2024