1. Group 3: Airplane! GOALS Students will investigate the role of variability in data collection. Students will engage in the hands-on process of data collection. Students will identify sources of error in data collection and offer methods of controlling these sources.

2. Activity Set-Up Student materials needed: calculators, paper Teacher materials needed: –Models for folding paper airplanes (as requested) –Instruction and data collection sheet –Measuring tape –Masking tape Prior skills required: –Calculate measures of center –Make graphs of data

3. Directions of Activity 1.Each group (about 3 students) must make a prediction about the distance that a paper airplane can fly, either radially or as measured perpendicular to the direction of release. 2.Each group must construct their paper airplane from their own paper. If no one in the group can make a successful paper airplane, models of folding will be provided. (See www.bestpaperairplanes.com )www.bestpaperairplanes.com

4. The “Zump” Model

5. Directions of Activity (continued) 3.Each group will launch their airplanes in repeated trials (as many as possible in a fixed amount of time or a fixed number of trials set by instructor). Data will be recorded in a table. 4.Each group will calculate a measure of center (mean, also perhaps median) for their distances, and then make a graph on the board, floor, or computer to represent their data. The type of graph may be at the discretion of the teacher and/or students.

6. Classroom Analysis Compare means and graphs of data from different groups. Key questions: –How can variability in the measurement of a single variable be observed in the graphs? –Why might different groups end up with clearly different mean flight distances? Can the entire class compile its data to find a single estimate for the mean flight distance of a paper airplane? Why or why not?

7. Discussion Students should realize that because each group had different models and launching techniques, it is NOT valid to simply gather data from all groups to get a class distance estimate. The key principle is to identify sources of variability that could have been controlled before beginning the activity.

8. Unintended Variability Students should generate a list of sources of variation between groups, such as: –Design of airplane –Angle of launch (may not have even been the same within a group throughout) –Distance measured from tip or tail –Wind –Experience of group members with airplanes –Type and size of paper used in construction –Level of damage to airplanes after repeated trials

9. Concluding Ideas Students should agree that a standardized launch process would help to minimize variability and find a more accurate estimate of the mean flight distance. Students should also recognize that variability still cannot be eliminated, either due to variables out of man’s control (wind) or to the inherent fact that planes won’t always fly the same distance every time.

10. Next Steps In future projects, students can be assessed on their ability to prepare a procedure that will enable all data-gatherers to follow an identical process for experimentation or surveying. Issues of sample size and standard deviation can be discussed later. Subsequent experiments (like predicting whether coins can be rolled down the hall farther than airplanes can fly) can lead to hypothesis tests for comparison of two means, and as an opportunity to demonstrate systematic procedures to avoid confounding variables.