Data Collection & Analysis Flashcards
7 cards from real CSM practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Data Collection & Analysis flashcards as text
Which statistical method is most appropriate for identifying the relationship between impervious surface percentage and peak runoff volume across multiple watersheds?
Answer: Linear regression analysis
Linear regression analysis quantifies the linear relationship between a continuous predictor (impervious cover %) and a continuous outcome (peak runoff), making it the most appropriate tool here.
A stormwater manager receives turbidity readings of 5, 6, 200, 7, and 5 NTU from five consecutive samples. The value of 200 NTU is most likely a(n):
Answer: Outlier requiring investigation
A single value orders of magnitude above the rest of the dataset is a statistical outlier and should be investigated for sampling error, equipment malfunction, or a true transient event.
When designing a stormwater monitoring network, the concept of 'spatial representativeness' requires that sampling locations:
Answer: Capture the range of land uses and sub-watershed conditions
Spatial representativeness means monitoring locations are chosen to reflect the variety of conditions across a watershed so data generalizes to the whole system.
A flow-weighted composite sample is collected by:
Answer: Taking aliquots proportional to instantaneous stream flow at each interval
Flow-weighted compositing adds aliquot volumes proportional to flow so the composite reflects actual pollutant mass loading rather than time-averaged concentration.
Which data quality indicator (DQI) addresses whether a measurement is close to the true or accepted reference value?
Answer: Accuracy
Accuracy (or bias) measures how close a result is to the true value, often assessed using certified reference standards or spikes.
The US EPA's NPDES Phase II permit requires small MS4s to track the effectiveness of BMPs. Which metric best quantifies pollutant load reduction?
Answer: Annual pollutant load (mass/year) before and after BMP installation
Annual pollutant load comparisons (concentration × flow volume × time) before and after BMP installation directly measure mass reduction, which is the relevant metric for permit compliance.
A stormwater dataset has a highly skewed distribution of pollutant concentrations. Which measure of central tendency is most appropriate to report?
Answer: Median
The median is resistant to the influence of extreme high values that are common in skewed stormwater pollutant datasets, making it a more representative central tendency measure than the mean.