Basics of Environmental Sampling and Analysis - Fundamentals of Environmental Sampling and Analysis - page 43

(2) Excel output of one-way ANOVA

Summary

Groups Count Sum Average Variance

EPA method 5 80.3 16.06 0.223

New method 5 81.9 16.38 0.852

ANOVA

Source of variation SS df MS F p-value F crit

Between Groups 0.256 1 0.256 0.4762791 0.5096343 5.317644991

Within Groups 4.3 8 0.5375

Total 4.556 9

23. Pyrene was analyzed using GC-MS at the selected ion mode. The calibration curve of
peak area (GC-MS response) vs. concentration is shown below along with the
regression output. A blank sample was analyzed seven times, giving a mean peak area
of 125 and standard deviation of 15. A check standard at 0.5 ppm was also measured
seven times, giving a standard deviation of 300. The raw data, Excel's printouts of
linear regression along with the line plot are attached. (a) Perform your own Excel
analysis and compare with what is given. (b) What are the linear regression equation
and the R 2 ? (c) What is the calibration sensitivity? (d) Is the linear regression
statistically significant, if yes then why? (e) If an unknown liquid sample (after a
dilution of 10 times) was injected into GC-MS and gave a peak area of 35720, what is
the concentration of this sample?

Concentration of GC-MS

pyrene (ppm) response

0 0

0.1 7456

0.2 14929

0.3 21219

0.4 28783

0.6 43496

SUMMARY OUTPUT

Regression Statistics

Multiple R 0.999793298

R Square 0.999586638

Adjusted R Square 0.999483298

Standard Error 353.7486093

Observations 6