Department of Mathematics Education
J. Wilson, EMAT 6680
EMAT 6680 Assignment #12:
Spreadsheet in
Mathematics
Matthew Tanner
EMAT 6680
Writeup #12
July 26, 2004
This data is from the lumber industry, giving the approximate number of board feet of lumber per tree in a forest of a given age. What function will fit the data? Predict the harvest for ages other than those given. 
The graph of the Tree Data depicts what the data
indicates and as you might otherwise expect – that the yield in board feet of
harvested timber increases with the age of the tree. 
Simple linear regression produces a model equation
that approximates the data. The
method of least squares seeks to minimize the error between the values
predicted by the model and the observed values. 
The slope of the least squares equation is given
by: . The yintercept is given by: . 

Simple linear regression approximates the observed
data in only a general way

Curve fitting functions in
Excel and numerical programming applications will interpolate polynomial
functions to the observed data. In
the case of the tree data, the available observations suggest an polynomial
function of degree two, 
Dedicated numerical
programming software such as Maple will interpolate a function to any
required precision. > with(CurveFitting): PolynomialInterpolation([[20,1],[40,6],[80,33],[100,56],[12 120,88],[160,182],[200,320]],
z); 
