# The following table relates ages, in years, of oak trees to their ba.pdf

2 de Apr de 2023
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### The following table relates ages, in years, of oak trees to their ba.pdf

• 1. The following table relates ages, in years, of oak trees to their base trunk circumferences, in inches. 1. Determine an exponential function, y = abx, that fits the data. Enter this model into y = with 3- digit accuracy. 2. Convert your exponential model in part b to base e. Use C as the independent variable and A as the dependent variable. 3. Convert your answer to part c to the simplest logarithmic form possible. 4. What would be the circumferences of oak trees planted half a century ago and a century ago? 5. Why might it make more sense to use the base circumference of a tree to predict its age rather than the base diameter?circumference (C)69.51112.5141516.51717.518age (A)8101214161820222426 Solution 1) I entered these coordinates into http://www.xuru.org/rt/ExpR.asp#CopyPaste : (6,8) (9.5,10) (11,12) (12.5,14) (14,16) (15,18) (16.5,20) (17,22) (17.5,24) (18,26) to get A = 3.9684e^(0.1015C) or A = 3.9684*(1.10683)^C as the equivalent exponential regression equation 2) In terms of e : A = 3.9684e^(0.1015C)
• 2. 3) A / 3.9684 = e^(0.1015C) Ln(A / 3.9684) = 0.1015C C = (1/0.1015) * Ln(A / 3.9684) C = 9.8522 * Ln(A / 3.9684) ---> This is equivalenmt Log equation 4) Half a century ago, A = 50 : C = 9.8522 * Ln(50 / 3.9684) = 24.96 units A century ago, A = 100 : C = 9.8522 * Ln(100 / 3.9684) = 31.79 units 5) The diameter is not visually accessible to us when looking at a tree, but the circumference is. So, it makes more sense to use the circumference rather than the diameter. And also, with passing time, nothing would be expected tp happen within a tree, but there would be effects seen to the outside surface, i.e the circumference of the tree