The rare earth element gadolinium is often used as a contrastingagent for MRIs. The concentration of gadolinium was measured in thedischarge from a wastewater treatment plant near a large medicalfacility. Eight measurements were obtained: 1.212001.21200 ppm,1.212001.21200 ppm, 1.209001.20900 ppm, 1.203001.20300 ppm,1.777001.77700 ppm, 1.201001.20100 ppm, 1.218001.21800 ppm,1.201001.20100 ppm.
Use the Grubbs test to determine if one of these values is anoutlier. What is the value of ?calcGcalc?
?calc=Gcalc=
Should this potential outlier be rejected with 95% confidence?Critical values of ?G can be found in this table.
The potential outlier should be rejected.
The potential outlier should be kept.
Based on the outcome of the Grubbs test, calculate the mean(?¯x¯), standard deviation (?s), and 99% confidence interval forthe results. A list of ?t values can be found in the Student's ?ttable.
?¯=x¯=
ppm
?=s=
ppm
confidence interval:?¯±x¯±
ppm
