Science Buddies: "Ask an Expert"

I have a certain layout my teacher has asked for.

Problem | Title of Project | Procedure
| |
Variables | Graphs/Charts/pictures | Results
| |
Hypothesis | | Conclusion
| |
Materials | More Pictures, etc. |


problem (I put this as purpose instead):

The purpose of my experiment is to prove that there is a fifty percent chance of at least two people in a random group of twenty-three people having the same birthday.

I am having trouble with Variables:

What am I changing? All I did was collect birthdays from 10 different groups of twenty-three.

What changed as a result? I didn't change anything, so how could something change as a result?

The control would be the number of people I am using. (23)

Hypothesis
I think that mathematically this is feasable, but in a real life situation it would not work out. This is because in real life, birthdays are not evenly distributed throughout the 365 days in a year and mathematically it would be very difficult to include odd variables like leap years, twins, etc.

Materials
I am probobly not going to include this because there are almost no materials. I only used paper and a pen/pencil.

Procedure
For my experiment, I distributed 10 forms in random classes. They were to be filled out by students. The information collected was the month and date of birth. After collecting the information, I was able to compare dates in each room and found that in most classes there was no more than a single match.

Results
The results of my experiment were as follows:

Group I - No Match
Group II - Two matches
Group III - No Matches
Group IV - One Match
Group V - One Match
Group VI - One match
Group VII - Six Matches
Group VIII - No Matches
Group IX - No Matches
Group X - Four Matches

Four Nos, three ones, one two, one four, and one six.

Conclusion
This experiment has proved that it is true that in a random group of twenty three people, there is at least a fifty percent chance of two of them having the same birthday. Six groups had at least one match, while only four had nothing at all.

Pictures/Graphics for the middle:
I don't know what I am going to put in the middle. I can put little pictures of birthday cakes and balloons, but I don't know what kind of graphs, models or tables I am going to use.

Things I need help with:

Pics, graphics and variables. Should I just cut variables out? What kind of Pictures and tables or graphs can I use?

Thanks

This seems like a very interesting project. For the pictures/graphs/tables part, you could include a table of the group and how many matches, just like you had in your post...

Group I - No Match
Group II - Two matches
Group III - No Matches
Group IV - One Match
Group V - One Match
Group VI - One match
Group VII - Six Matches
Group VIII - No Matches
Group IX - No Matches
Group X - Four Matches

...I don't think you need to talk about when those dates were or anything like that because your purpose is to prove that there's a 50% chance that in a random group of 23 people, birthdays will match. (By the way, when you say there were 6 matches, do you mean that there were six pairs of people with the same birthday or that six people had the same birthday? You should try and clarify that a bit when you do your report.) If you need some more stuff for the middle, how about just a copy of the form you passed out?

The variables are a bit of a strange point... You keep the number of people constant. The only thing you change is the group of 23 people... hmmm... I'm going to say that you can talk about your control in your variables section and also talk about just changing the group of people. I'm not sure if that's really a variable, but part of your purpose to prove that the 50% statement holds true in random groups of 23. So you are just repeating one trial for more data. You are not seeing how something changes. I don't think it's a variable (I could be wrong), but I think you have something to talk about in that section: you kept your group the same size and just changed who was in it.

Another small point you should talk about is why you chose 23 for the group size. That should go somewhere too.

I hope that helps! If you have any questions, comments, or whatever, I'll get back to you.

1. If I'm not mistaken, this project can also be performed using a theoretical approach for which you could compare your empirical results with.
2. Note that you may want to detail exactly how students were picked for the experiment. Especially for an experiment like this, the word "random" may not be sufficient.
3. Regarding your conclusion, I'd suggest sticking in the bold text:

"This experiment has proved that it is true that in a random group of twenty three people, on average there is at least a fifty percent chance of two of them having the same birthday. Six groups had at least one match, while only four had nothing at all."

My rationale: If I'm not mistaken, it is very probable that at least 50% of the time a pair will share the same birthday. However, since there does exist a possibility that even given random groups, there are no matches, I highly recommend inserting the two words "on average."

4. I'm under the impression that the variable is the number of birthday matches, which may seem kind of counterintuitive.

Correction: Ignore the third bullet point in my previous post.

Thanks for your help!

I have almost finished my project. All I have to do now is glue the sutff to the poster and I'll be set for tomorrow!


Thanks