A performance test for a video streaming service shows that while the average response time for the 'start playback' action is 1.5 seconds, the 95th percentile is 4.8 seconds. The target is 95% of requests under 3 seconds. What does this discrepancy most likely indicate?

The test is invalid because the average and percentile do not match.

The 95th percentile is an outlier and should be ignored.

The average is misleading; a significant portion of users experience response times above the target.

The system is performing well because the average is within the target.

What is the primary purpose of interpreting performance metrics?

To replace the need for load testing in future projects.

To determine if the system's performance meets the defined targets and to identify potential issues.

To automatically fix any performance issues found.

To provide a summary for marketing purposes only.

A startup is developing a mobile app and has limited budget for performance testing. The product owner wants to focus on the user experience, while the CTO is concerned about infrastructure costs. Which approach to metric selection best balances these concerns?

Collect a small set of user-centric metrics (e.g., response time percentiles) and a few key resource metrics (e.g., CPU and memory) to identify cost drivers.

Collect every possible metric to ensure no data is missed.

Collect only infrastructure metrics to minimize cost.

Collect only business metrics like revenue per transaction.

A financial services company is performance testing a new trading application. The stakeholders are primarily concerned about user experience during market hours, but the operations team also needs to plan capacity for future growth. Which metric selection best addresses both stakeholder needs?

Only average response time and error rate

Response time percentiles and throughput, along with resource utilization trends

Only CPU and memory utilization of servers

Network latency and bandwidth usage only

During a load test, the performance tester observes that the response time for a critical transaction is within target, but the application server's memory usage is steadily increasing and the garbage collection (GC) time is also increasing. The test is only halfway through the planned duration. What is the most appropriate action?

Monitor the trend and consider extending the test duration to see if the memory usage stabilizes or continues to grow.

Stop the test immediately and report a memory leak.

Reduce the load to see if memory usage decreases.

Continue the test as planned because response time is within target.

Certified Tester Performance Testing

Domain 2Objective 1

Why Performance Metrics Are Needed CT-PT Practice Questions (Page 3)

Part of the Performance Measurement Fundamentals domain, which makes up ~28% of our current practice bank. ISTQB does not publish an official question count, but from its 90-minute exam (~35–60 total, ~10–17 in this domain), expect 2–3 from this objective — we provide 21 practice questions to prepare you well beyond it. (estimate)

21questions here

5free pages

4concepts

Questions 11–15

11application · medium
A performance test for a video streaming service shows that while the average response time for the 'start playback' action is 1.5 seconds, the 95th percentile is 4.8 seconds. The target is 95% of requests under 3 seconds. What does this discrepancy most likely indicate?
Select an answer first
12foundation · easy
What is the primary purpose of interpreting performance metrics?
Select an answer first
13application · medium
A startup is developing a mobile app and has limited budget for performance testing. The product owner wants to focus on the user experience, while the CTO is concerned about infrastructure costs. Which approach to metric selection best balances these concerns?
Select an answer first
14application · medium
A financial services company is performance testing a new trading application. The stakeholders are primarily concerned about user experience during market hours, but the operations team also needs to plan capacity for future growth. Which metric selection best addresses both stakeholder needs?
Select an answer first
15expert · hard
During a load test, the performance tester observes that the response time for a critical transaction is within target, but the application server's memory usage is steadily increasing and the garbage collection (GC) time is also increasing. The test is only halfway through the planned duration. What is the most appropriate action?
Select an answer first

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