Explanation
Equivalence partitioning is a technique to divide a set of possible inputs or outputs into classes that are expected to behave similarly or produce similar results. For each equivalence class, only one test case is required to represent the whole class. In this case, we can identify the following equivalence classes for the input field 'ZIP code':
Valid ZIP code format and valid ZIP code value (e.g., 12345)
Valid ZIP code format and invalid ZIP code value (e.g., 99999)
Invalid ZIP code format and valid ZIP code value (e.g., 1234)
Invalid ZIP code format and invalid ZIP code value (e.g., ABCDE)
Therefore, four test cases are required to test this field using equivalence partitioning.
References: Certified Tester Foundation Level Syllabus, Section 4.4.1

Explanation
To cover 100% statement coverage, we need to execute every statement in the code at least once. To cover
100% decision coverage, we need to execute every branch in the code at least once. The minimum number of test cases required to achieve both statement and decision coverage is 4 for statement and 5 for decision. Here is one possible set of test cases:
| Test Case | Input | Output | Statement Coverage | Decision Coverage | | TC1 | Walking = True, Midnight = False, Raining = False, Running = False | Take umbrella | S1, S2, S3, S4, S5 | D1-T, D2-T | | TC2 | Walking = False, Midnight = True, Raining = False, Running = False | Search light | S1, S2, S6, S7 | D1-F, D3-T | | TC3 | Walking = False, Midnight = False, Raining = True, Running = False | Take umbrella and search light | S1, S2, S6, S8, S9 | D1-F, D3-F, D4-T | | TC4 | Walking = False, Midnight = False, Raining = False, Running = True | Keep doing what you were doing | S1, S2, S6, S8, S10 | D1-F, D3-F, D4-F |

Explanation
Managing the incidents in a spreadsheet posted on the intranet is the best option for a QA manager of a start-up company who needs to implement within a week a low cost incident management tool. A spreadsheet is a simple and flexible tool that can be used to record, track, and report incidents. Posting the spreadsheet on the intranet can make it accessible and visible to the relevant stakeholders. This option can be implemented quickly and cheaply, without requiring much training or maintenance3 suggests this as follows:
A spreadsheet is a common tool that can be used for incident management, especially for small or simple projects. A spreadsheet can be used to create an incident report template that includes the necessary information and fields for each incident. The spreadsheet can also be used to sort, filter, group, or analyze the incidents based on various criteria. The spreadsheet can be shared or published on a network or web location that can be accessed by the project team and other stakeholders.
A, C, and D are not good options for a QA manager of a start-up company who needs to implement within a week a low cost incident management tool. Managing the incidents through E-mails and phone calls (A) is not a good option, as it can be inefficient, unreliable, and inconsistent. E-mails and phone calls can be easily lost, overlooked, or forgotten, and they do not provide a centralized or structured way of recording, tracking, or reporting incidents. Purchasing and deploying an incident management tool is not a good option, as it can be expensive, time-consuming, and complex. An incident management tool may require licensing fees, installation costs, configuration efforts, training sessions, and maintenance support. Documenting incidents on a large board in the lab (D) is not a good option, as it can be impractical, insecure, and incomplete. A large board in the lab may not have enough space or structure to document all the incidents in detail, and it may not be accessible or visible to all the stakeholders. A large board in the lab may also expose confidential or sensitive information to unauthorized people.

Explanation
Tests designed by a person in the development team other than the person who wrote the code is not the lowest level of independence. The lowest level of independence is tests designed by the person who wrote the code, as this may introduce bias or blind spots in testing. Tests designed by another person in the development team is one level higher than tests designed by the person who wrote the code, as this may provide a different perspective or expertise in testing. defines the levels of independence as follows:
The level of independence of testing is related to the degree of separation between those who are responsible for developing software and those who are responsible for testing software.
The following levels of independence can be distinguished:
Level 0: No independent testing; tests are designed by the same person who wrote the code.
Level 1: Tests are designed by another person in the development team; e.g., another programmer or software designer.
Level 2: Tests are designed by a person from a different group within the organization; e.g., an independent test team or group.
Level 3: Tests are designed by a person from a different organization or company; e.g., an outsourcing partner or contractor.
A, B, and C are correct statements. A test team with high level of independence may suffer from lower familiarity with the product (A), as they may not have access to all the information or knowledge about the system under test. Development team may find many defects since they are familiar with the code (B), as they may have more insight into how the system works internally and where potential problems may occur. Tests designed by a person from different group in the organization is the highest level of independence within an organization, as this provides maximum separation between development and testing activities.

Explanation
One of the basic principles of testing is that for a software system, it is not possible under normal conditions to test all input and output combinations because they are too many and too complex to cover within a reasonable time and budget. Therefore, testers have to select a subset of inputs and outputs that are representative and relevant for testing based on criteria such as requirements, risks, priorities, etc. This principle implies that testing cannot prove that a software system is defect-free or has a certain level of quality because there might be some untested inputs or outputs that could reveal defects or failures. Testing can only provide information about the quality and risk level of a software system based on the observed behavior and results under certain conditions and assumptions. You can find more information about the basic principles of testing in A Study Guide to the ISTQB Foundation Level 2018 Syllabus, Chapter 11.