In this video segment from Cyberchase, the CyberSquad explains to Ms. Fileshare how Hacker deceived her by using a different number scale on his bar graph. They explain to her that comparing two graphs with different scales is not an accurate comparison. This segment is the third of three segments. Check out “Inventing Bar Graphs” to see how the CyberSquad created their bar graph. Then watch “Attention to Scaling” to see how they discover the difference between Hacker's bar graph and the one they created.
Here are some Frame, Focus and Follow-up suggestions for using this video in a math lesson.
What is Frame, Focus and Follow-up?
Frame: When we look at a bar graph and see numbers alongside the lines on the graph, we are looking at the number scale. If you were going to make a bar graph of the number of hours you watched TV every day for one week, what kind of number scale might you use? What would be the lowest number on the scale? What would be the highest?
Focus: As you watch this video segment, decide why Hacker chose to use large numbers on his number scale. What was it about the CyberSquad’s graph and explanation that finally convinced Ms. Fileshare that she was being tricked by Hacker?
Follow Up: What was the number scale on the CyberSquad’s bar graph? Did it make sense to use that particular scale to represent the data they collected? Is it a fair comparison when you compare two bar graphs that use different number scales? Why or why not?
MS. FILESHARE: But I'm much too busy to go look at any more graphs.
JACKIE: No problem, Ms. Fileshare, we're bringing them to you!
MATT: Pointing fingers without knowing all the facts was wrong, Ms. Fileshare.
MATT: The Vermin Vexer did use the same numbers for his bar graph that we did. But there's more. Look.
MATT: Both graphs have number scales now – they didn't before.
MS. FILESHARE: Hmmm, fourteen on yours... and one hundred five on his?!
INEZ: Yep. The Vermin Vexer used really big numbers on his scale so the data bars would look tiny.
JACKIE: And tiny bars make it look like there's only a few bugs in all the sections. Jackie gestures to their graph.
JACKIE: We chose a scale with smaller numbers so the bars would be bigger and easier to understand.
MATT: But large or small, Ms. Fileshare, fourteen bugs is fourteen bugs!
MID-SHOT: Ms. Fileshare is convinced.
MS. FILESHARE: Well, flip my files!
INEZ: There's more. Watch!
HACKER/VERMIN VEXER: Look at these. You can clearly tell I got rid of a lot more bugs than he did last year.
MS. FILESHARE: Wait! Those graphs aren't a fair comparison!
MATT: Add scales to them, and look what you see...
MS. FILESHARE: The other guy caught waaay more bugs than the Vermin Vexer!
MS. FILESHARE: He deliberately left off the scales to make it look like he was better. I've been bamboozled!
INEZ: We made the same mistake...until we found out the sizes of the bars on a graph don't tell the whole story.
MATT: The power is in the whole picture! You have to think about the numbers and the scale, too.
INEZ: Then you can figure out what the graph is really saying.
Academic standards correlations on Teachers' Domain use the Achievement Standards Network (ASN) database of state and national standards, provided to NSDL projects courtesy of JES & Co.
We assign reference terms to each statement within a standards document and to each media resource, and correlations are based upon matches of these terms for a given grade band. If a particular standards document of interest to you is not displayed yet, it most likely has not yet been processed by ASN or by Teachers' Domain. We will be adding social studies and arts correlations over the coming year, and also will be increasing the specificity of alignment.