Page 332 - Excel for Scientists and Engineers: Numerical Methods

CHAPTER 13 LINEAR REGRESSION AND CURVE FITTING 309

Problems

Data for, and answers to, the following problems are found in the folder "Ch. 13
(Linear Regression)" in the "Problems & Solutions" folder on the CD.

1. The calibration curve data in Table 13-1 shows readings taken on a series of
sodium standards, using a CIBA-Corning Model 410 flame photometer. The
calibration line is noticeably curved.

Table 13-1. Data for flame photometry calibration curve.
Fit the data to a cubic equation, y = ax3 + bx2 + cx + d.

2. If any of the coefficients found in problem 13-1 have unacceptably large
standard errors, repeat the analysis using a different fitting function.

3. Fit the data In Table 13-2 (also available on the CD) to a power series
function, y = axb, using (a) Trendline and (b) LINEST.

Table 13-2. Data to be fitted with a power series.