Exam CTFL_Syll_4.0 Topic 1 Question 52 Discussion
Actual exam question for ISQI's CTFL_Syll_4.0 exam
Question #: 52
Topic #: 1
Question #: 52
Topic #: 1
Following a risk-based testing approach you have designed 10 tests to cover a product risk with a high-risk level. You want to estimate, adopting the three-point test estimation technique, the test effort required to reduce the risk level to zero by executing those 10 tests. You made the following three initial estimates:
* most optimistic = 6 person hours
* most likely = 30 person hours
* most pessimistic = 54 person hours
Based only on the given information, which of the following answers about the three-point test estimation technique applied to this problem is true?
* most optimistic = 6 person hours
* most likely = 30 person hours
* most pessimistic = 54 person hours
Based only on the given information, which of the following answers about the three-point test estimation technique applied to this problem is true?
Suggested Answer: A Vote an answer
The three-point test estimation technique is a method of estimating the test effort based on three initial estimates: the most optimistic, the most likely, and the most pessimistic. The technique uses a weighted average of these three estimates to calculate the final estimate, which is also known as the expected value. The formula for the expected value is:
Expected value = (most optimistic + 4 * most likely + most pessimistic) / 6 Using the given values, the expected value is:
Expected value = (6 + 4 * 30 + 54) / 6 Expected value = 30 person hours However, the expected value is not the only factor to consider when estimating the test effort. The technique also calculates the standard deviation, which is a measure of the variability or uncertainty of the estimates. The formula for the standard deviation is:
Standard deviation = (most pessimistic - most optimistic) / 6
Using the given values, the standard deviation is:
Standard deviation = (54 - 6) / 6 Standard deviation = 8 person hours
The standard deviation can be used to determine a range of possible values for the test effort, based on a certain level of confidence. For example, using a 68% confidence level, the range is:
Expected value ± standard deviation
Using the calculated values, the range is:
30 ± 8 person hours
Therefore, the final estimate is between 22 person hours and 38 person hours, which is option A.
Expected value = (most optimistic + 4 * most likely + most pessimistic) / 6 Using the given values, the expected value is:
Expected value = (6 + 4 * 30 + 54) / 6 Expected value = 30 person hours However, the expected value is not the only factor to consider when estimating the test effort. The technique also calculates the standard deviation, which is a measure of the variability or uncertainty of the estimates. The formula for the standard deviation is:
Standard deviation = (most pessimistic - most optimistic) / 6
Using the given values, the standard deviation is:
Standard deviation = (54 - 6) / 6 Standard deviation = 8 person hours
The standard deviation can be used to determine a range of possible values for the test effort, based on a certain level of confidence. For example, using a 68% confidence level, the range is:
Expected value ± standard deviation
Using the calculated values, the range is:
30 ± 8 person hours
Therefore, the final estimate is between 22 person hours and 38 person hours, which is option A.
by Ursula at Oct 28, 2024, 02:04 PM
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