CHM121 Topic II: Evaluation of Analytical Data

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What is the main goal in performing a chemical analysis?

To measure uncertainties accurately

To eliminate errors and uncertainties

To produce a scatter of results

To estimate the true value with acceptable accuracy (correct)

Why is the true value for any quantity always unknown in chemical analysis?

Due to the experimenter's fault

Since measurement uncertainties can never be completely eliminated (correct)

Because of faulty calibrations or standardization

Because of the scatter of results

What is the significance of evaluating the magnitude of error in chemical analysis?

To determine the experimenter's fault

To produce a scatter of accurate results

To eliminate errors and uncertainties

To define limits for the true value with a given level of probability (correct)

Why are data of unknown quality considered worthless in chemical analysis?

To address and estimate the reliability of the data Signup and view all the answers

What is the middle value of a sample of results arranged in order of increasing/decreasing magnitude?

Median Signup and view all the answers

Which value is used advantageously when a set of data contains an outlier?

Median Signup and view all the answers

What does the mode represent in a set of determinations?

The highest value Signup and view all the answers

Which term describes the reproducibility of measurements and deals with repeatability and reproducibility?

Precision Signup and view all the answers

What is used to describe how close the results are, provided that they are obtained in exactly the same way?

Precision Signup and view all the answers

Which measure is calculated by dividing the sum of replicate measurements by the number of measurements in the set?

Mean Signup and view all the answers

What does standard deviation from the mean represent?

Absolute error Signup and view all the answers

What does accuracy indicate about measurements?

Closeness to true value Signup and view all the answers

"Precision" deals with which type of variability?

Within-runs and between-runs Signup and view all the answers

"Mode" represents which value in a set of determinations?

'x' such that f(x) is maximum Signup and view all the answers

What is used to estimate the uncertainty associated with the central value?

All of the above Signup and view all the answers

CHM121 Topic II: Evaluation of Analytical Data

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