CIH CIH - Certified Industrial Hygienist Sampling Strategy and Statistical Analysis Questions and Answers 2

Question 1

What does a coefficient of variation (CV) represent in the context of analytical method performance?

Accepted Answer

The relative standard deviation, expressing precision as a percentage of the mean

Answer

The coefficient of variation (CV) is the relative standard deviation expressed as a percentage of the mean, used to quantify the precision (reproducibility) of an analytical method.

Question 2

According to OSHA's compliance sampling strategy, what constitutes an overexposure finding for an 8-hour TWA?

Accepted Answer

The measured TWA exceeds the PEL after accounting for sampling and analytical error

Answer

OSHA considers an overexposure confirmed when the measured TWA exceeds the PEL even after subtracting the combined sampling and analytical error (CSAE) from the result.

Question 3

What is the purpose of a field blank in industrial hygiene air sampling?

Accepted Answer

To detect and correct for contamination introduced during sample handling and shipping

Answer

A field blank is an unexposed sample handled identically to field samples to detect contamination from transport, handling, or environmental sources that would falsely elevate results.

Question 4

When sampling for a substance with a ceiling limit (C), what is the correct sampling duration according to OSHA guidelines?

Accepted Answer

15-minute short-term samples taken during peak exposure periods

Answer

Ceiling limits apply to 15-minute short-term exposures at times of expected peak concentrations; OSHA requires short-term sampling during maximum exposure conditions to evaluate compliance.

Question 5

What statistical tool is used to determine whether measured 95th percentile exposure significantly exceeds an OEL using lognormal exposure data?

Accepted Answer

Land's exact method or lognormal upper confidence limit on the 95th percentile

Answer

Land's exact method calculates the upper confidence limit (UCL) on the 95th percentile of a lognormal distribution, which is the standard approach for evaluating whether upper-tail exposures exceed the OEL.

CIH - Certified Industrial Hygienist Exam Practice Test

CIH - Certified Industrial Hygienist Exam Practice Test

CIH CIH - Certified Industrial Hygienist Sampling Strategy and Statistical Analysis Questions and Answers 2