The following results were obtained for the determination of calcium in a NIST l
ID: 789583 • Letter: T
Question
The following results were obtained for the determination of calcium in a NIST limestone sample: % = 50.31, 50.22, 50.38, 50.19, and 50.45. Five gross samples were then obtained for a carload of limestone. The average percent values for the gross samples were found to be 49.46, 50.11, 49.62, 49.76, and 50.30. Calculate the overall relative standard deviation, the relative standard deviation of the method, and the relative standard deviation of the sampling process.
The following results were obtained for the determination of calcium in a NIST limestone sample: % = 50.31, 50.22, 50.38, 50.19, and 50.45. Five gross samples were then obtained for a carload of limestone. The average percent values for the gross samples were found to be 49.46, 50.11, 49.62, 49.76, and 50.30. Calculate the overall relative standard deviation, the relative standard deviation of the method, and the relative standard deviation of the sampling process.Explanation / Answer
average of NIST limstone = 50.31
average of gross samples = 49.85
standard deviation of NIST limstone = 0.10839
standard deviation of gross samples = 0.3475
avrg standard deviation = 0.22797
relative standard deviation, RSD = 100S/x
100*0.22797/50.08 = 0.4552