Question

Below is the data for the optical densities observed during analysis of solutions with 5 different concentrations of API (OD1 and OD2 are two measurements for the same solution).

Conc, mg/L	OD1	OD2
5	0.126	0.098
10	0.208	0.194
25	0.515	0.492
50	0.996	1.201
100	1.960	2.090

1. Using Minitab, develop regression equation for the relationship of Mean OD (need to calculate it first!) versus concentration of API and make a plot showing the data and the regression line. Show 95% confidence intervals for that regression line.
2. Make the same plot but show 95% prediction intervals for that regression line.
3. What can you say about the ability to use that line as a calibration line for the analysis of future samples with unknown concentrations of the same API?

Answer 1

Solution:

Using minitab we solve this problem as below

therefore

a)

Regression Equation is

conc = -0.59 + 48.97 mean OD

where Y = cocn mg/L

And X = mean of OD1 and OD2

b)

95% prediction intervals for that regression line.

c)

Using the above information we say that there is  line as a calibration line for the analysis of future samples with unknown concentrations of the same API then it predict with high accuracy because Confidence interval line is near to the regression line hence it show the high accuracy and all the data points are lies within 95% confidence interval therefore we gate the high accuracy.

Thank You..!!

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