The correct answer is B, as it describes checklist-based testing.Checklist-based testing is an experience-based test technique that involves a list of tests based on what is important to the user as well as an understanding of why and how software fails1.Checklist-based testing can be used to ensure that important aspects of the software are tested and to guide the tester in creating additional tests1.Option A is incorrect, as checklist-based testing provides some consistency and guidelines concerning test case development by using predefined lists of items or criteria to check against1.Option C is incorrect, as checklist-based testing is not restricted to non-functional testing, but can be used for both functional and non-functional testing1.Option D is incorrect, as checklist-based testing does not include formal tests from detailed lists of test conditions, but informal tests from high-level lists of items or criteria1. Reference:1, Section 4.2.6

They should be involved in reviewing requirements or user stories as soon as drafts are available is the option that represents good testing practice for testers, irrespective of the software lifecycle model used, because it allows testers to provide early feedback, identify potential defects, and clarify test objectives and scope1.Early involvement of testers in reviewing requirements or user stories can improve the quality and testability of the software and reduce the cost and effort of testing1. The other options do not represent good testing practice for testers, irrespective of the software lifecycle model used.Option A is not a good option, because they should start test analysis as early as possible, not when the corresponding development level is complete, to avoid delays and inefficiencies in testing1.Option C is not a good option, because they should ensure that different test objectives apply to each test level, not the same test objectives, to avoid redundancy and gaps in testing1.Option D is not a good option, because they should minimize the ratio of development levels to test levels to reduce project costs, but rather balance the development and test levels according to the project needs and risks1.

According to the syllabus, the choice of a particular type of software development life cycle (SDLC) model depends on various factors, such as project size, complexity, scope, budget, schedule, quality requirements, risk level, customer involvement, etc. The type of product being developed is one of the most important factors that influences the selection of an SDLC model, as different products may have different characteristics, expectations, and challenges that require different approaches to development. For example, a product that has well-defined and stable requirements may benefit from a sequential SDLC model like waterfall or V-model, while a product that has vague or changing requirements may benefit from an iterative SDLC model like incremental or agile. The answer D is correct because it best reflects the reason for selecting a particular type of SDLC model. The other answers are incorrect because they are not good reasons for selecting a particular type of SDLC model. Tester skill level with the SDLC model (A) may affect the effectiveness and efficiency of testing activities, but it should not be the primary factor for choosing an SDLC model. Testers should be able to adapt to different SDLC models depending on the project context and objectives. The project manager's preference (B) may reflect their personal experience or opinion, but it should not be the sole factor for choosing an SDLC model. The project manager should consider various factors and consult with other stakeholders before selecting an SDLC model. The project team's overall familiarity with the model may affect the productivity and collaboration of the team members, but it should not be the main factor for choosing an SDLC model. The project team should be able to learn and apply different SDLC models depending on the project context and objectives.

Less than 0, 1 to 80, more than 80 is a valid collection of equivalence classes for the following problem: ''An Integer numeric field shall contain values from 1 to 80 both values inclusive''. Equivalence partitioning is a technique to divide the input domain into partitions that are expected to behave similarly or produce the same output.Each partition should have at least one representative value as a test case2explains equivalence partitioning as follows:

Equivalence Partitioning (or Equivalence Class Partitioning) is an software testing technique that divides the input data of a software unit into partitions of equivalent data from which test cases can be derived. In principle, test cases are designed to cover each partition at least once.

The fundamental concept of Equivalence Partitioning is that you can find more errors in a test case by using a representative value from an equivalence class than by using any other value from the class.

The input domain for this problem can be divided into three partitions: less than 0, 1 to 80, and more than 80. The first and the last partitions are invalid, as they are outside the range of acceptable values for this field. The middle partition is valid, as it is within the range of acceptable values for this field.

A, C, and D are incorrect answers. A does not include 0 as an invalid partition. C does not include 0 as an invalid partition. D does not include 80 as a valid partition.

Testing is the process of evaluating a software product by learning about it through exploration and experimentation, which includes running tests, observing outcomes, making inferences, and creating and refining test ideas. Testing has many objectives, such as finding defects, providing information, improving quality, reducing risks, etc. One of the objectives of testing is preventing defects, which means avoiding or minimizing the occurrence of defects in the software product by applying good practices and techniques throughout the software development life cycle. Preventing defects can help to save time, cost, and effort in testing and development, and improve customer satisfaction and confidence. A detailed explanation of testing objectives can be found in [A Study Guide to the ISTQB Foundation Level 2018 Syllabus], pages 7-8.