# Standard:MAFS.8.SP.1.2 CREATING A LINEAR MODEL Know that straight lines are widely used to model relationships between two quantitative variables. For.

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Standard:MAFS.8.SP.1.2 CREATING A LINEAR MODEL Know that straight lines are widely used to model relationships between two quantitative variables. For scatter plots that suggest a linear association, informally fit a straight line, and informally assess the model fit by judging the closeness of the data points to the line.

Warm Up A.(6, 15) B.(6, 9) C.(8, 12) D.(9, 7) E.(10, 12) F.(12, 15) Graph the following points on the coordinate grid

Vocabulary Scatter Plot Positive and Negative Correlation Line of Best Fit

Scatter Plot A scatter plot is a graph of a collection of ordered pairs. The graph looks like a bunch of points. The points show the relationship between two sets of data. The points on the graph can move in a general direction.

Positive Correlation We call it a positive correlation when both the x-coordinates and the y- coordinates increase simultaneously.

Positive Correlation The more hours the person worked, the higher the income. Both x and y are increasing simultaneously. Hours worked daily24681012 Income (in dollars)163248648096

Negative Correlation We have a Negative Correlation when one variable is increasing and the other is decreasing. In this case the graph goes downhill. x25810121416327 y201615141087181716

Negative Correlation Temperature Outside 102030354045505560 Heating Bill140115110958082755535

No Correlation The points are scattered. There is no pattern. The points are not related There is no correlation

No Correlation

Recap Identify the correlation below. Label as positive, negative or no correlation. _____________ 12 3

Line of Best Fit The line of best fit is the straight line that best represents the data on a scatter plot. may pass through all of the points, some of the points, or none of the points. can be used to make predictions as to what can happen if the trend continues. represents a relationship between two quantities.

Lines of Best Fit

Guided Practice Years of experience 156101115202535 Income (hourly wage) 2029442949 604555 Hours Watch TV 011.522.533.545 Test Score928985807068605560 2