30 Questions
What is the depth range of the soil samples collected in this study?
0-10 cm
At each distance from the road, how many samples were taken and combined to form a single sample?
10 samples
What is the purpose of combining the 10 samples taken at each distance into a single composite sample?
To decrease sampling uncertainty
Why were samples collected at fixed distances from the road?
Both a and c
What type of sampling plan is used in this study?
Systematic-judgmental sampling
Which of the following is a type of sample that could have been collected in this study?
All of the above
What is the main purpose of controlling pH, temperature, and light exposure when preserving samples?
To maintain the chemical composition of the samples
Which of the following is NOT an example of a gaseous sample mentioned in the text?
Pharmaceutical products
What is the main advantage of using stainless steel canisters or Tedlar/Teflon bags for urban air sampling?
Simplicity and representative sampling
What is the primary reason that minimal preservation or preparation is needed for gaseous samples collected via solid sorbents, filters, or cryogenic cooling methods?
The samples are more stable due to the collection method
How can the quantity of gaseous compounds collected via solid sorbents be determined?
By measuring the increase in sorbent mass if selective absorption occurs
Which of the following is NOT an example of a solid sample mentioned in the text?
Compressed gases
What is the primary advantage of stratified sampling over random sampling?
It reduces sampling error
Which statement best describes systematic-judgmental sampling?
Sample sites are chosen systematically based on researcher judgment
Which sampling method is most appropriate for preliminary or exploratory research?
Convenience sampling
In stratified sampling, what is a stratum?
A subset of the population that shares a common characteristic
Why might stratified sampling be used when one stratum has a low incidence relative to others?
To ensure that the low-incidence stratum is adequately represented
In the study described, which sampling method was likely used to select sites for measuring pollutant concentrations in roadside soils?
Systematic-judgmental sampling
What is the primary reason for the need for careful sampling when dealing with solids?
Solids are typically heterogeneous
What is the purpose of the flexible metal leaves on the bottom of the gravity corer?
To prevent sediment from escaping as the corer is hauled back to the surface
What is the purpose of the riffle shown in the example?
To divide a gross sample into four piles for further processing
What is the purpose of the sample thief shown in the diagram?
To collect a sample of the sediment
What is the primary reason for the importance of preservation mentioned in the text?
All of the above
What is the primary purpose of the grab sampler shown in the diagram?
To collect a sample of the sediment
What is the primary concern when designing a sampling plan for a quantitative analysis?
Accurately representing the composition of the target population
Which of the following is NOT a consideration when designing a sampling plan?
The maximum amount of sample that can be collected
What is a sampling error?
When the sample's composition is not identical to the target population
In a homogeneous target population, what is true about the composition?
It is the same regardless of where, when, or the size of the sample
In a qualitative analysis, what is the requirement for the sample?
There must be sufficient analyte present to ensure its detection
When analyzing a trace-level component, what might be desirable when collecting samples?
Discriminating against major components
This quiz covers the concept of standard deviations resulting from sampling and analytical methods. Topics include designing a sampling plan to support analysis goals and ensuring detection of analytes in qualitative analysis. The quiz emphasizes the importance of accuracy in identifying trace-level components.
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