NCA-GENL Data Analysis and Visualization Practice Question
A data scientist is profiling an LLM inference service on NVIDIA GPUs and has collected per-request latency samples. The distribution has a long right tail caused by a small number of requests that queue behind large batches. Which pair of summary statistics BEST communicates both the typical experience and the tail pain to the engineering team?
⚠ Common exam trap
The trap here is defaulting to mean and standard deviation for latency, when a right-skewed distribution makes those statistics misrepresent the typical request and the tail.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Median and p99 latency.
For right-skewed latency, the median represents the typical request and p99 captures the tail that frustrates users. Reporting them together lets the team see that most requests are fast while a small fraction suffer queueing delay. Mean and standard deviation blur both facts, and min/max or mode/range discard the distribution entirely, so they cannot guide batching or scheduling changes.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Mode and range.
Why it's wrong here
The mode of continuous latency is sensitive to binning and often meaningless, and the range is determined by a single extreme sample. Neither summarizes the typical case or the size of the tail population. Range in particular tells the team nothing about how many requests are slow, so it cannot guide queueing fixes.
- ✗
Minimum and maximum latency.
Why it's wrong here
Minimum and maximum describe only the extremes and ignore the entire distribution between them. The minimum is usually an unrealistic best case, and the maximum is one noisy request. With a long tail, the team needs to know how common slow requests are, which these two numbers never reveal.
- ✗
Mean and standard deviation.
Why it's wrong here
Mean and standard deviation assume a roughly symmetric distribution and are both pulled upward by a long right tail. The mean would overstate the typical request, and the standard deviation would be inflated, hiding the fact that most requests are fast. They do not isolate the tail behavior that the team needs to diagnose queueing.
- ✓
Median and p99 latency.
Why this is correct
The median shows the typical request unaffected by the tail, while p99 exposes the worst-case experience that users actually notice. Together they separate 'most requests are fine' from 'one percent are painfully slow', which points directly at queueing behind large batches. This pairing is standard for latency reporting on inference services.
About these practice questions
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official NVIDIA exam blueprint
This NCA-GENL practice question is part of Courseiva's free NVIDIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the NCA-GENL exam.