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Student Response
The best t line is since it goes right through the middle of the data. Every point is either 1 above or 1 below the line.
Activity Synthesis
The goal is to make sure that students understand that a best t line models the shape of the data and goes through the middle of the data.
• “Why is not the line of best t?” (It goes through the upper half of the points but it does not go through the center of the data.)
• “How many points does the line of best t pass through? Is this okay?” (It goes through zero points. This is okay because the line of best t models the trend of the data and goes through the middle of the data.)
• “How far away are the data points on the -axis away from the -intercept of the line of best t?” (They are both one unit away. One is one unit above the -intercept and the other is one unit below the -intercept.)
• “Can you think of another model that might t this data well?” (Due to the regularity, it might make sense to use two separate lines that t the data perfectly rather than one line that ts everything ok.)
6.2 Oranges Return
15 minutes
This lesson uses the data from the video of orange weights from lesson S2.A1. The mathematical purpose of this activity is to introduce the concept of residuals, and to have student plot and
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Teacher Guide
Algebra