A team is analyzing response times over a 1-hour test. They aggregated the data into 5-minute intervals and noticed that the average response time increases every interval. What is the most likely conclusion?

The test is invalid because of the trend

The load is decreasing over time

The system is degrading over time, possibly due to a memory leak or resource exhaustion

The system is improving over time

A team is aggregating response times and finds that 1% of samples are extremely high (e.g., 20 seconds) while the rest are around 1 second. They have confirmed these high values are due to a network issue during the test. What is the most appropriate way to handle them?

Replace them with the average response time

Include them in the aggregation to be conservative

Exclude the samples caused by the network issue and note it in the report

Ignore them without documenting

A team is analyzing a 24-hour test. They aggregated response times into 1-hour intervals. In the first hour, they see a spike to 10 seconds, but the rest of the hours are around 2 seconds. The team wants to determine if the system is stable. What should they do?

Investigate the first-hour spike to determine if it is an outlier or a real issue

Conclude the system is unstable because of the spike

Use the median of all hourly averages to conclude stability

Ignore the first-hour spike and conclude the system is stable

A team ran the same test scenario twice: once with 50 users and once with 100 users. They want to compare the average response times. What is the most appropriate way to normalize the data?

Divide the response times by the number of users

Use the maximum response time from each run

Use the median response time from each run

Compare the response times at the same load level, e.g., the 50-user run with the first 50 users of the 100-user run

Certified Tester Performance Testing

Domain 2Objective 4

Aggregating Results from Performance Testing CT-PT Practice Questions (Page 5)

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 30 practice questions to prepare you well beyond it. (estimate)

30questions here

6free pages

7concepts

Questions 21–25

21application · medium
A team is analyzing response times over a 1-hour test. They aggregated the data into 5-minute intervals and noticed that the average response time increases every interval. What is the most likely conclusion?
Select an answer first
22application · medium
A team is aggregating response times and finds that 1% of samples are extremely high (e.g., 20 seconds) while the rest are around 1 second. They have confirmed these high values are due to a network issue during the test. What is the most appropriate way to handle them?
Select an answer first
23application · medium
A team has raw response-time data in a spreadsheet. They need to calculate the 90th percentile for a transaction. Which spreadsheet feature should they use?
Select an answer first
24expert · hard
A team is analyzing a 24-hour test. They aggregated response times into 1-hour intervals. In the first hour, they see a spike to 10 seconds, but the rest of the hours are around 2 seconds. The team wants to determine if the system is stable. What should they do?
Select an answer first
25application · medium
A team ran the same test scenario twice: once with 50 users and once with 100 users. They want to compare the average response times. What is the most appropriate way to normalize the data?
Select an answer first

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