Page 138 - IM_Algebra1_FL Print Sample.pdf

c. Least to greatest vertical intercept of a linear model that ts the data well.
2. For each card, write a sentence that describes how changes as increases and whether the linear model is a good t for the data or not.
Student Response
1. The order for each sort is: a. B, A and F, C, E.
b. E, B, C, A and F. c. A,C,F, B, E
2. Sample responses:
a. As increases, also increases. The linear model ts the data fairly well.
b. As increases, decreases. The linear model ts the data very well.
c. As increases, increases. The linear model ts most of the data very well; however, there are two values that do not follow this trend.
d. As increases, well at all.
e. As increases, point at
f. As increases,
g. As increases, at all.
Activity Synthesis
goes up and down like a wave. The data does not follow the line very
decreases. Most of the data ts a linear model very well, but the one dot not t with the rest of the data very well.
increases. The linear model ts the data fairly well.
decreases and then increases. The data dots not follow the line very well
Unit 3
Lesson 5: Fitting Lines 71
The purpose of this discuss is for students to discuss the goodness of t for linear models. Here are some questions for discussion.
• “How are scatter plots of A and F the same? How are they di erent?” (They have the same slope and the linear model for each scatter plot are equally well t. They are di erent because they have a di erent vertical intercept.)
• “How do you know if a linear model is a good t?” (You need to look at the scatter plot and the line of best t and make a decision about whether or not the data follows a linear trend.)
• “Why is the goodness t for the linear model in scatter plot B better than the t for the linear model in scatter plot A?” (The data in B falls on or very close to the linear model. The data in A is scattered around the line of best t and has roughly the same amount of values below that line of best t as it does above the line of best t.)