The data in the table below were obtained during a colorimetric determination of glucose in blood serum.
Glucose Absorbance,
concentration, NM A
0.0 0.002
2.0 0.150
4.0 0.294
6.0 0.434
8.0 0.570
10.0 0.704
(a) Assuming a linear relationship, find the least-squares estimates of the slope and intercept.
(b) Use the LINEST function in Excel to find the standard deviations of the slope and intercept. (See S.R. Crouch and F.J. Holler, Applications of Microsoft® Excel in Analytical Chemistry, Belmount, CA: brooks/Cole, 2004, Chap.4) What is the standard error of the estimate?
(c) Determine the 95% confidence intervals for the slope and intercept.
(d) A serum sample gave an absorbance of 0.350. Find the glucose concentration and its standard deviation.