16.9 The following data pertain to the chlorine residue in a swimming pool at various times after it has been treated with chemicals: Number of hours Chlorine residual (parts per million) 2.2 2 1.8 4 1.5 6. 1.4 8. 1.1 10 1.1 12 0.9 where the reading at 0 hour was taken immediately after the chemical treatment was completed. (a) Use the computing formulas on page 466 to fit a least-squares line from which we can predict the chlorine residual in terms of the number of hours since the pool has been treated with chemicals. (b) Use the equation of the least-squares line obtained in part (a) to estimate the chlorine residual in the pool five hours after it has been treated with chemicals. (c) Suppose you discover that the data for this exercise were obtained on a very hot day. Explain why the results of parts (a) and (b) might be quite misleading.

16.9 The following data pertain to the chlorine residue in a swimming pool at various times after it has been treated with chemicals: Number of hours Chlorine residual (parts per million) 2.2 2 1.8 4 1.5 6. 1.4 8. 1.1 10 1.1 12 0.9 where the reading at 0 hour was taken immediately after the chemical treatment was completed. (a) Use the computing formulas on page 466 to fit a least-squares line from which we can predict the chlorine residual in terms of the number of hours since the pool has been treated with chemicals. (b) Use the equation of the least-squares line obtained in part (a) to estimate the chlorine residual in the pool five hours after it has been treated with chemicals. (c) Suppose you discover that the data for this exercise were obtained on a very hot day. Explain why the results of parts (a) and (b) might be quite misleading.

Linear Algebra: A Modern Introduction

4th Edition

ISBN:9781285463247

Author:David Poole

Publisher:David Poole

Chapter7: Distance And Approximation

Section7.3: Least Squares Approximation

Problem 34EQ

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