Data collection and storage activities are focused on ensuring that the data is adequate, unique, and consistent.
This involves:
* Adequacy: Ensuring that the collected data meets the necessary requirements for its intended use.
* Uniqueness: Verifying that the data is not duplicated and is uniquely identifiable.
* Consistency: Ensuring that the data is consistent across different datasets and over time.
These activities are critical for maintaining the integrity and reliability of the data, which is essential for effective data analysis and decision-making.
References:
* "Data Quality: The Accuracy Dimension" by Jack E. Olson
* "Data Management for Researchers" by Kristin Briney

Functional testing is a type of software testing that evaluates the functionality of a software application by testing it against the specified requirements. The primary goal of functional testing is to ensure that the software works as per the desired specifications and performs its intended functions correctly123.
* Is sufficiently free of operational problems (Option A): One of the main objectives of functional testing is to demonstrate that the software operates correctly and is free of issues that could affect its operation. This includes testing the software to ensure that it is performing its required functions without errors or problems12.
* Is understood by the user (Option B): While user understanding is important, it is not the primary objective of functional testing. User understanding is more related to usability testing, which assesses how easily users can learn and use the product.
* Interacts appropriately at the unit level (Option C): Interaction at the unit level is typically tested during unit testing, which is a subset of functional testing but not its overarching objective. Functional testing looks at the application as a whole rather than individual units2.
* Processes the data in a structured manner (Option D): Although processing data correctly is part of functional testing, the focus is on whether the software performs its intended functions and not specifically on the structure of data processing.

Boundary value testing is used to check the behavior of the system at the boundaries of input ranges. Time zones often have critical boundaries, such as the change from one day to the next or the switch between standard time and daylight saving time.
* Boundary Value Analysis: Tests the values at the edges of equivalence classes, which in the context of time zones could include:
* Transition points between time zones
* Daylight saving time changes
* Leap years and the end/start of months
* Efficiency: Testing boundaries is typically more efficient than testing all possible values, especially when dealing with large ranges like time zones.
* Application: Ensures that the software handles edge cases correctly, such as the change from 11:59 PM in one time zone to 12:00 AM in another.

Negative testing, also known as failure testing, aims to ensure that a system can handle invalid input or unexpected user behavior gracefully. The testing design used to evaluate this includes:
* Fault Insertion:This involves deliberately inserting faults into the system to check how it behaves under erroneous conditions. The goal is to verify that the system can detect, handle, and recover from faults effectively.
References:
* Software Testing and Quality Assurance by Kshirasagar Naik and Priyadarshi Tripathy
* ISTQB (International Software Testing Qualifications Board) guidelines