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Houghton Mifflin Harcourt Algebra 1, 2015

HM

Houghton Mifflin Harcourt Algebra 1, 2015 View details

2. Fitting a Linear Model to Data

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Exercise 20 Page 373

Make a table of values to calculate the residuals.

The line is not a good fit.

Practice makes perfect

The following table shows the median age of people living in Texas.

Year	Median Age of People
1970	27.1
1980	29.3
1990	31.1
2000	33.8
2010	37.6

We will use the residuals to to calculate the quality of fit for the line y=0.5x+20.

x	y (Actual)	y predicted by y=0.5x+20	Residual for y=0.5x+20
0	27.1	y=0.5( 0)+20= 20	27.1- 20=7.1
10	29.3	y=0.5( 10)+20= 25	29.3- 25=4.3
20	31.1	y=0.5( 20)+20= 30	31.1- 30=1.1
30	33.8	y=0.5( 30)+20= 35	33.8- 35=-1.2
40	37.6	y=0.5( 40)+20= 40	37.6- 40=-2.4

As you can see, the residuals are large. Therefore, the line is not a good fit.

Subchapter links

Explore p.364-369

Elaborate p.369

Evaluate: Homework and Practice p.369-374

Lesson Performance Task