McNamara, Carolee and Michael

LaSalle Academy

86 Overhill Road

Providence, RI 02906





Linear Trends



	This text is about the use of a straight line to fit a data set. All 

the data sets in the documents are time series.  The text treats graphic, 

numerical and analytical approaches to the problem.

	Lines are first "fit" to a single print and to two points. Then lines 

are fit to several points using only graphical sense, and a measure of fit 

is introduced for these lines. Finally, the semi-average algorithm is used 

to determine a line that fits.

	The text is appropriate for any precalculus student, who has been 

introduced to slopes, linear equations, and linear graphs.



The purposes of the text are 

*	to show precalculus students that notions of slope and line are useful 

and important. 

*	to reinforce linear ideas and techniques. 

*	to give the user a simple and practical tool for analyzing certain 

data sets 

*	to show that useful applications can be accessible.

The text includes problems and some open-ended questions.

	Note: "Linear Trends" is planned as a part of a series of applications 

of precalculus mathematics. This series will include such applications (of 

precalculus topics) as: 

*	Index numbers  (sigma notation, presentation of data)

*	Exponential trends (exponential functions, logarithms) 

*	Size of a herd (matrix arithmetic, exponential data fit) 

*	Binary sequences (compositions of functions, periodicity) 

*	Cyclic phenomena (trig functions) 

Two of these document are now drafts being used to test the interactive 

aspects of the material.







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