Self-test 3.1 – Estimation of measurement uncertainty in chemical analysis

Now you can test whether you have understood the normal distribution and the related concepts well.

Which of the following statements about measurements, measurands, distribution functions and the normal distribution are correct?

1. If repeated measurements are performed and the distribution function is known then it is possible to exactly predict the value of every next measured value.

True

False

2. Results of repeated measurements of the same measurand are often normally distributed.

True

False

3. The maximum of the normal distribution curve corresponds to the mean value of the repeated measurement results if a large number of repetitions are made.

True

False

4. Standard deviation characterizes the scatter of the values obtained from repeated measurements.

True

False

5. Standard uncertainty is obtained by multiplying the standard deviation by a coverage factor.

True

False

6. If the result is normally distributed then the coverage factor 3 enables calculating expanded uncertainty with 100% coverage probability.

True

False

7. Which coverage factor has to be used in order to have expanded uncertainty estimate with confidence level of approximately 95%? It is known, that there is normal distribution.

2.5