DA0-002 Data Acquisition and Preparation Practice Question
Which data sampling method involves selecting every k-th element from a list after a random start?
⚠ Common exam trap
DA0-002 often tests the confusion between systematic (every k-th) and stratified (proportional subgroups) sampling — candidates mix up the interval-based method with the subgroup-based method.
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
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Systematic sampling
Systematic sampling selects every k-th element from a list after choosing a random starting point. For example, with k=10 and a random start of 3, you pick elements 3, 13, 23, and so on. This makes it efficient for large, ordered populations while still providing a probabilistic sample.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Systematic sampling
Why this is correct
Systematic sampling selects every k-th element after a random starting point, directly matching the stem's definition. The random start prevents bias from periodic patterns in the list, while the fixed interval k ensures even coverage across the dataset. This satisfies the constraint of deterministic interval selection combined with randomised initiation.
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Cluster sampling
Why it's wrong here
Cluster sampling selects entire naturally occurring groups and then samples within or across them, rather than stepping through a list at fixed intervals. It is tempting because it also divides the population, but the random-start-plus-every-k-th procedure is systematic sampling.
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Stratified sampling
Why it's wrong here
Stratified sampling partitions the population into homogeneous strata and draws randomly within each, so selection is not driven by a fixed k-th interval. It is tempting because it also uses random starts within groups, but the stem describes systematic sampling, not stratification.
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Simple random sampling
Why it's wrong here
Simple random sampling gives every element an equal independent chance of selection, producing no fixed interval between chosen items. It is tempting because it is the baseline probability method, but the described procedure of a random start followed by every k-th element is systematic sampling.
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
This DA0-002 practice question is part of Courseiva's free CompTIA 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 DA0-002 exam.