BEARS IN SPACE

Marshall Jiang3rd Period

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Design of ExperimentThe purpose of this experiment was to determine how far a GummiBear can be sent into space by a launcher and the effect on the launch distance by the angle and the position of the launch pad. An experiment was chosen as the method of study for this question due to the fact that our group cannot just observe GummiBears launching into space, thus we have to deliberately create an experiment.

The nature of this experiment dictates us that GummiBears are to be used as the experi-mental units of this experiment. Our explanatory variables would be the launch angle (de-termined by the number of books) and the launch position (determined by the position of the launcher on the ruler). The response variable is the length the GummiBear after it was at rest from the end of the ruler. Treatment is as follows where top is the top of the ruler and bottom at the bottom of the ruler:

Blocking in this experiment was determined to be of no use as our group determined that outside variables are to their minimal. This was determined due to the fact that most of the GummiBears looked like they are similar in almost every physical aspect with the exception of colors and slight variations of the shape.

Blinding is only single blinding as the bears are not conscious of the treatments they are re-ceiving. The reason it is not double-blind is because the measurer, our group, was fully aware the treatment the bear received.

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Random allocation

Group 1: 5 subjects

Group 2: 5 subjects

Group 3: 5 subjects

Group 4: 5 subjects

Group 5: 5 subjects

Group 6: 5 subjects

Treatment 1: 1 book, top

Treatment 2: 1 book, bottom

Treatment 3: 3 book, top

Treatment 4: 3 book,bottom

Treatment 5: 5 book, top

Treatment 6: 5 book, bottom

Compare length of launch

Description of Set UpFirst of all, get a pack of GummiBears with at least 30 bears in it too ensure that enough bears are launched for replication and to ensure control as they should be of the same type. Create the launcher with two popsicle sticks and two rubber bands by wrapping one rubber band around both sticks and the other rubber band around only one stick. Now gather 5 “The Practice of Statistics: 3rd Edition” textbooks and a meter stick. Place the meter stick on the book as shown in the picture below with around half an inch at the top:

Now follow the experiment by random allocating the 30 GummiBears into 6 groups of 5 GummiBears each. To create the treatment group, just stack the textbooks on top of each other by the amount indicated in the diagram drawn under Design of Experiment. The posi-tion of the launcher is either at the very top with the back parallel to the back of the ruler, or at the bottom with the front parallel to the front of the ruler. Now just place the Gum-miBear on top of the launcher and pull back the the popsicle stick and let go quickly.

When the GummiBear finally stops bouncing around, measure the distance the GummiBear went by only measuring how far the GummiBear went forward, not sideways, starting from the end of the ruler at the ground.

This way we could implement, as best as we could, the three principles of experimental de-sign: control and replication was gained by purchasing the GummiBears in one large pack of the same types of bears (large amounts of bears and the same types of bears), and random-ness was gained by the random allocation of the bear into the groups.

Data and AnalysisTable (The format of the column is “number of books: position”; all measurements are in inches):

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T R I A L 1 T R I A L 2 T R I A L 3 T R I A L 4 T R I A L 5 A V E R A G E

1: Top -5.5 -7.5 -11 -2 -10 -7.2

1: Bottom 18 21 21 17.5 15 18.5

3: Top -3 -7 -6 -3 -8 -5.4

3: Bottom 23 24 26 23 18.5 22.9

5: Top 5 -1 1 -2 0 0.6

5: Bottom 29 33 23 37 17 27.8

As you can see by the graph (5 books, top position cannot be seen that well due to a hard scale), there is clearly a great improvement (statistically significant) if you move from top to bottom or increase the book height. Accordingly, the maximum distance seems to be with 5 books at the bottom of the meter stick.

I think it is quite reasonable for me to say that there’s a strong correlation between either increasing the book height, or moving the launcher to the bottom, with increased distance launched. But the data from two groups of my classmates seems to somewhat disagree with me.

-15.0

-7.5

0

7.5

15.0

22.5

30.0

1: Top 1: Bottom 3: Top 3: Bottom 5: Top 5: Bottom

Average Distance Launched in Inches

Laun

ch L

engh

t in

Inch

es

Treatment

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Group 2 seems to have more data resembling mine, as the general shape of the bar histo-gram looks like mine but both Group 1 and Group 2 have the same conclusion in terms of book angle: the more the better. The placement of the launcher differs though, as Group 2 suggests the bottom of the 5 book one while Group 1 suggests the top of the 5 book stack.

A V E R A G E A V E R A G E

1: Top 14.6 6.8

1: Bottom 45.5 70.5

3: Top 45.1 18.7

3: Bottom 42.6 68.2

5: Top 65.7 38.3

5: Bottom 60.8 82.3

Group 1 Group 2

0

22.5

45.0

67.5

90.0

1: Top 1: Bottom 3: Top 3: Bottom 5: Top 5: Bottom

Other Group’s Launch Data in Inches

Laun

ch L

engh

t in

Inch

es

Treatment

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After analyzing the design after doing it, there’s a few places where it could be improved upon. First of all, the lurking variable of measuring the GummiBear after it bounced proba-bly proved to be a bit of a bad judgement. The second possible lurking variable is that the human launcher got better at launching the bears as time went on (this is what happened to Group 1 as I consulted their group why their data are like that). I would fix the first one by measuring the distance at the point where the GummiBear first hit the ground and the sec-ond one could be fix by either creating a mechanical launcher that doesn’t need a human op-erator or use a new person for every launch.

There was also significant bias in where we measured the distance from as then the launch-ers from the bottom of the ruler gets a some 35ish inches of advantage over the ones in the back. To correct this, we could measure the distance from where we launched instead to correct for this bias.

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