Question

Your boss asked you to evaluate a new analytical method for the determination of creatinine in blood samples. To complete the assignment, you proceed to determine a standard 58.1 nmol/L solution of creatinine by applying the established method used in the lab (A) and the new method (B) suggested by your boss. Repeated determinations obtained from 100.0 L aliquots of standard solution gave the following results:

a) Which method incurs in the smaller absolute deviation from the known content of creatinine in the standard? Explain why. (A)

b) Which method affords the worse reproducibility? Why? (A)

c) Which has the larger range with 95% confidence? Why? (A)

d) Are the two methods statistically different from each other with 95% confidence? Why? (yes)

established(A) new (B)

57.9 nmol/L 60.3 nmol/L

58.4 nmol/L 59.9 nmol/L

56.5 nmol/L 59.7 nmol/L

58.1 nmol/L 60.1 nmol/L

57.3 nmol/L

Answer 1

1. standar deviation of methods:

A: 2.1275 nmol/L

B: 0.2 nmol/L

It is clear, the method B has the lowest STD because the values to not change that much from the mean.

2. Reproducibility is related to precision, and this last is bonded to STD becasue this means you measured more than once and many values hit the same target. It does not means accuracy. Method B.

We can gladly help you with the other but you should post them again. HINT:Use statistical methods to solve.