CSI Orlando
CSI Orlando
Can you catch the k iller?
Description
Students randomly choose colored blocks from a set of bags to determine which two bags have
matching contents. They are allowed to choose only one block at a time, and must put it back.
Objectives (Lessons to be learned)
The law of large numbers
Probability versus raw data.
Sunshine State Standards/Benchmarks
MA.E.2.4.2 determines the probability for simple and compound events as well as
independent and dependent events
MA.E.3.4.1 designs and performs real-world statistical experiments that involve more
than one variable, then analyzes results and reports findings.
MA.E.3.4.2 explains the limitations of using statistical techniques and data in making
inferences and valid arguments.
Bodies of Knowledge (Approved September 2007)
MA.912.S.1.1 Formulates an appropriate research question to be answered by collecting
data or performing an experiment.
MA.912.S.1.2 Determine appropriate and consistent standards of measurement for the
data to be collected in a survey or experiment.
Relevance
Why is sample size so important and why data is often displayed in percentages in the real
world?
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Discrete Mathematics
CSI Orlando
Learning Challenges
Inquiry Questions
How many samples did you take? Is that enough?
How did you compare the data you collected? Could there be a better way to
compare the results from each bag?
Conclusion Statement
To get an accurate picture of what is in the bags you have to sample many times
the number of blocks in the bag.
Probability is the best way to compare sets of data and make an inference.
The “Aha!” Moments
When they realize they have to increase sample size and compare with percentage
Tools Needed
5 brown paper bags
40 red chips blocks or tiles
20 blue chips blocks or tiles
10 green chips blocks or tiles
Inquiry Procedure/Assignment
There were five people murdered last night in Orlando; three strangers and two siblings! DNA was
collected from each body and taken to the crime lab for analysis. However, Lonnie the loser lab tech
mixed up the paper work for each murder victim’s DNA sample and he no longer knows which sample is
for which person.
He knows that the DNA for the siblings will match, so if he can find those two, he will narrow the
problem down. It is your job to help Lonnie figure out which DNA sample belongs to the two siblings.
The DNA for each of the five murder victims is coded with colored cubes located in each of five paper
bags. There is ONE catch! You cannot look in the bags…you must pull out one cube, record its color and
put it back in the bag. You are allowed to do this as many times for each bag as you want, but you cannot
look in the bag.
Your team needs to:
1. Decide how many trials you are going to conduct on each person’s bag.
2. Conduct the experiment.
3. Organize your results in some way in order to make a prediction concerning who the siblings are.
4. Present your findings to the whole class.
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Discrete Mathematics
CSI Orlando
For each team, write the names of each murderer on one of five brown paper lunch bags. Put the
following number of tiles, cubes, or chips in the corresponding bag:
Red Blue Green
Angie 9 1 1
Bob 7 2 2
Charles 4 6 1
Donavan 7 2 2
Ernie 9 2 0
Tell the CSI Orlando story, but do NOT reveal how many colors are possible in each bag. You can tell
them there are 14 in each, or to make it more challenging, you can keep that hidden as well. If you tell
them how many cubes are in each bag, many students will just conduct 14 trials and make an erroneous
decision. If you do not tell them how many cubes in each bag, it leaves it open for students to choose a
variety of number of trials.
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Discrete Mathematics