The primary goal of HCI is to design interactive systems that are easy to use, efficient, and enjoyable, thereby enhancing user satisfaction and productivity.

Cost-effective design is not a core principle of HCI. The primary focus of HCI is on enhancing user experience and usability, rather than solely minimizing costs.

Task analysis is a technique used in HCI to understand the tasks that users need to perform with an interactive system. This information is crucial for designing an interface that effectively supports user goals and requirements.

User testing is an HCI evaluation method where users are observed while interacting with a system to identify usability issues and gather feedback on the user experience.

Prototyping in HCI is used to create tangible representations of design concepts, allowing designers and users to evaluate the usability and functionality of these concepts before committing to a final design.

Natural language processing is not a common type of interaction technique in HCI. It is a field of artificial intelligence that deals with the interaction between computers and human (natural) languages.

Cognitive walkthrough is an HCI evaluation method where experts walk through a series of tasks, simulating the thought process of a user, to identify potential usability issues and areas for improvement.

Command-line interface (CLI) is not a common type of user interface in modern computing. It is a text-based interface that requires users to type commands to interact with the system.

Heuristic evaluation is an HCI evaluation method where experts use a set of predefined usability heuristics to identify potential usability issues in an interface.

A/B testing is not a common type of user-centered design method. It is a method used to compare different versions of a design or interface to determine which one performs better.

Iterative design is a design process in HCI where a design is developed through multiple cycles of feedback and revision, allowing designers to refine and improve the design based on user feedback and evaluation results.

A/B testing is not a common type of HCI evaluation method. It is a method used to compare different versions of a design or interface to determine which one performs better.

Focus group is an HCI evaluation method where a small group of users are brought together to discuss their experiences, opinions, and suggestions regarding a particular design or interface.

Natural language processing is not a common type of interaction device. It is a field of artificial intelligence that deals with the interaction between computers and human (natural) languages.

The primary goal of user-centered design in HCI is to design interactive systems that are easy to use, efficient, and enjoyable, thereby enhancing user satisfaction and productivity.