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Why?. Most students in science courses know how to graph. Why?. Most students in science courses think they know how to graphThis exercise lets them discover what they know and don't knowSelf-assessment is usedResult better graphs!. Learning Outcomes. Define termsStudents create and assess g
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1. Graphing Scientific Data From a
Mathematics Across the Curriculum (MAC)
coordinated studies class
with Biology 201 (Fall 2000)
at Edmonds Community College
Melissa Mackay (Math)
Jenny McFarland (Biology)
2. Why? Most students in science courses know how to graph
3. Why? Most students in science courses think they know how to graph
This exercise lets them discover what they know and dont know
Self-assessment is used
Result better graphs!
4. Learning Outcomes Define terms
Students create and assess graphs
Students create graphs in small groups
Critique graphs in large group
Students develop graphing rubric
Students practice self-assessment
Self-assess graphs in lab reports
Students choose appropriate graphs for particular data sets
Scatter plots & line graphs
Bar graphs & histograms
Pie charts
5. Define the following terms:
dependent variable
independent variable
scatter graph
line graph
bar graph
pie graph or chart
best fit line
slope
interpolation
extrapolation
6. Group Exercise For the set of data assigned, create a graph/chart that you think best displays the data.
Use the graph paper (if needed) and colored pencils
Groups will share graphs with large group.
7. Data
8. Graphing Rubric/Criteria Students in class or lab session develop rubric
Appropriate, descriptive title
Axes
dependent & independent variables on correct axes
labels
units
good scaling
Clear data points (easy to differentiate different symbols)
Key (if plotting more than one set of data)
Appropriate line-fitting
best-fit line
curve-fitting
connecting dots
Use graph paper or computer-generated graphs
9. Student Self-assessment Student self-assessment
is crucial to student learning
requires students to understand assessment criteria
requires that students do some critical analysis of their work, usually improving the product
allows students to take responsibility for their work
empowers students - so they know when they have performed well and do not rely on the instructors assessment alone
10. Self-assessment example From Biology 201 Photosynthesis Lab report:
Graph the absorbance spectra measured in your lab session.
What type of graph did you use? Why? (Explain your graph choice.)
Evaluate your graphs for this lab report. Are they excellent, adequate or poor? Can a reader look at this graph and know what you did? What criteria are you using to evaluate your graphs? Be explicit; list the criteria and state how you met each one.
11. Bad Graphs - Scaling
Bad scaling is a common problem in student graphs.
Students often need to see several examples. Presenting opportunities for students to assess graphs with bad scaling will help them recognize this and give them practice with better scaling alternatives.
From: Making Graphs http://scipp.ucsc.edu/~mothra/ta/graph/graph.html
12. Bad Graphs - missing information What is missing? Students often have information missing from their graphs.
Self-assessment helps students catch these omissions.
This problem is complicated by missing information in many textbook figures, where graph axes might not be labeled or may not have units.
From: http://www.ecs.umass.edu/ece/ece211/ECE211_graphing_techniques.html
13. Bad Graphs - area Multidimensional variation occurs where two-dimensional figures are used to represent one-dimensional values. The size of the graphic is scaled both horizontally and vertically according to the value being graphed. This results in the area of the graphic varying with the square of the underlying data, causing an exaggerated effect in the graph.
This graph has a lie factor of about 2.8, (variation between the area of each doctor & the number it represents).
Students do not usually generate this type of graph, but they often see it in the media.
From: Pitfalls of Data Analysis (or How to Avoid Lies and Damned Lies) by Clay Helberg, M.S.
Tufte, E.R. (1983). The Visual Display of Quantitative Information. Cheshire, CT: Graphics Press. p. 69